The Deterioration and Preventive Conservation of a Caboodle of Cosmetics

Makeup has been used for millennia; from the kohl remnants found in Egyptian tombs, the dangerous arsenic powders of the 1600s, lead white paints of the nineteenth and early twentieth centuries, and of course, into the modern day. It is therefore, not shocking, that makeup has found its way into museum collections. 

As a part of the LGBT+ collecting initiative, the Missouri Historical Society has acquired a makeup Caboodle from the late drag performer; Michelle McCausland. This case demonstrates a wide range of makeup that the artist used up until 2020. This includes lipstick in a range of shades, powders, eyeshadows, and more niche items like glue sticks.

This makeup box was clearly well-loved and well-used by the owner and provides an excellent window into the behind-the-scenes of drag performances. Unfortunately, this, in itself, presents a number of issues regarding conservation. 

Object Condition

Whilst the box itself is stable, there is serious surface soiling on both the exterior and interior. Furthermore, the contents of the box demonstrate severe surface soiling from its use-life and there is the distinct smell of old oil when the box is opened. Evidence of makeup debris can be seen in several compartments and several of the cosmetics are missing their lids. 

t was determined that the box and its contents should not be cleaned in order to preserve the history of the objects’ use. However, the distinct odour that emanates from the box is concerning. This smell suggests the off-gassing of the contents, which could cause further deterioration of the cosmetics, the box itself, and potential nearby artefacts. It is therefore imperative to understand the decay of the cosmetics present and identify what may be causing the problem, as well as determine a potential remedy.

The Composition of Makeup

There are three primary types of modern makeup; emulsions or liquid makeup, such as liquid foundation have an alcohol and oil base, gelled makeup such as lipstick are oil and wax based, and powdered makeup is made of talc. These bases are combined with a number of pigments and preservatives that vary between types of cosmetics and their manufacturers. 

Preservatives such as alcohols, parabens, isothiazolone derivatives, and phenol derivatives act as biocides in order to protect the product from microbial decay (MakingCosmetics Inc.). However, the efficacy of these compounds deteriorate over time, and the addition of skin oils during use only expedites this process. 

The Deterioration of Makeup

As a general recommendation from both manufacturers and beauty blogs, makeup products generally expire one year after their manufacture date (Logan, 2021). Shelf life does vary somewhat between products, depending on; the ingredients and formula, its manufacturing process, the purity of the ingredients, and the storage of the cosmetic. Most products demonstrate a number followed by an “M” on the container, which recommends the number of months the product can safely be used. This varies between products, with powders averaging one year, gels for six months, and liquids for three months. These recommendations are primarily based on the effectiveness of the preservatives over time and are also affected by how the cosmetic is applied. Pump containers last longer than those directly applied or applied with a reusable applicator due to the limited interaction with air or skin bacteria. 

The decay of preservatives leads to a number of chemical reactions within products that are less than ideal in their use life. Powders, such as foundation, are prone to oxidation, which may cause discolouration over time (Logan, 2021). Furthermore, many of the oils used in lipstick are susceptible to oxidative cross-linking, chain scission, and yellowing through the incorporation of oxygen (Mills and White 2003 via Homberger and Patterson, 2009). Oil components can also spoil and separate over time, which was recognised with samples in Visionaire magazine, collected by the New York Public Library (Riedell, 2009). Gel and liquid cosmetics are also prone to dust and particle accumulation over time if they are left exposed to the environment. Dust is hydroscopic, causing the build up of water that can further interact with the product and accelerate rancidity (Homberger and Patterson, 2009). Particulate matter like dust also causes an increase in bacterial and mould growth. 

A further issue with older cosmetics is the deterioration of the packaging. Museums have recognised bursting plastic and metallic tubes (Riedell, 2009; Wilcop, 2022) and stickiness from the loss of plasticisers in containers made of polyvinyl chloride (PVC). Although this may not directly impact the contents, it must be considered regarding the object’s stability as a whole.

Why is this a Problem?

It is expected that most objects will decay, at some level, over time. This includes those produced in the modern era. However, as institutions continue to grow and “modern” materials become more common in collections, it becomes imperative that materials such as cosmetics are preserved for the future. 

The primary concern with the deterioration of cosmetics in collections is the release of Volatile Organic Compounds (VOCs). VOCs are gaseous compounds that can cause the deterioration of a wide range of materials, especially metals. The most common compounds recognised in collections are acetic acid (from cellulose acetate or modern unsealed wood cases) and formic acid (commonly from paint or wood). The degradation of both the cosmetics themselves and their containers poses concerns for the release of VOCs into the atmosphere, causing damage to surrounding objects as well as the contents of the box itself. The suspicion regarding VOCs comes from the distinct “old makeup” and “old oil” smells that are apparent when the box is opened (Wilcop et al., 2018). Using gas chromatography-mass spectroscopy (GC-MS), volatile compounds including aldehydes, ketones, and some alcohols have been identified in deteriorating cosmetics (Ibid; Thomsen et al., 2017). Furthermore, plastics such as PVC and polymethyl methacrylate (PMMA) have also been determined to release VOCs as they decay (Curran and Strlic, 2015). These products can accelerate the deterioration of metals and organic materials that may be in contact or in the same environment, causing a wider problem in collections than the deterioration of a single object. It is thus imperative that the risk posed by the compounds is reduced as much as possible. 

Another problem recognised with the deterioration of modern cosmetics is the possibility of mould and bacterial growth. Mould begins to grow within makeup containers due to moisture build up over time (Mayo Clinic). Emulsion-type formulas (liquid cosmetics) are the most prone to mould and bacteria, whereas powders are the least. However, the growth of microorganisms is exacerbated through the use of products, particularly those in pots or plates that are regularly handled (compared to pumps which limit oxygen/moisture ingress into the contents). The use and reuse of makeup against skin causes the microflora and bacteria on skin surfaces to contaminate the makeup, thus leading to greater growth (Poucher and Butler, 1993). Not only is this less than ideal during the uselife of products, but also causes their continued deterioration after their entrance to collections. Furthermore, if not properly sealed, the mould and bacteria can spread to other objects within the same environment, causing wider concern for the museum’s collection at large.

Preventive Conservation

This Caboodle in particular is clearly deteriorating, based on both the recognisable smell of the makeup. Beyond this, we utilised an acid-base indicator strip (A-D strip) in order to determine the level of offgassing. This test came back positive, suggesting the need for intervention to limit the acidic deterioration of the makeup, caboodle, and other objects that may be in close vicinity.

In order to limit both the deterioration of the cosmetics themselves, as well as ensure that potential off-gassing and mould do not affect larger collections, preventive measures must be undertaken. Industry standards recommend that cosmetics should be stored below 20 degrees celsius and 55% relative humidity (RH) (Homberger and Patterson, 2009). Fortunately, these are the recommended conditions for museum collections on the whole and thus does not require further intervention whilst in storage and on display. However, light exposure has been seen to cause an increase in deterioration of a range of cosmetics including liquid and gel forms (Thomsen et al., 2017). Exposure to light accelerates lipid oxidation, which causes their breakdown and the degradation of products and the aforementioned smell of old oil (ibid). Thus, the lower lux value in both storage and display environments is important, as well as limiting the hours exposed. Ultra-violet radiation also causes deterioration in both cosmetic products and their containers. UV light can cause the breakdown in the preservatives in cosmetics, leaving them vulnerable to bacterial and mould growth. Therefore, it is important to limit UV light as much as possible. 

Since the object is going to be displayed as a part of the Missouri History Museum’s Gateway to Pride exhibit, it was decided that further steps should be undertaken in order to limit possible deterioration as much as possible. Carbon paper was used to line the different levels of the makeup box. This paper acts as a pollution catcher and helps absorb the VOCs the contents may emit over time, as well as gives the object a cleaner finish whilst still looking used.

Furthermore, silica gel was added to the box to stabilise the RH. Although the relative humidity of both storage and display locations is intended to be within a safe range, this further secures the object against fluctuations that may cause deterioration. Finally, to ensure that the exposure of other objects is limited, the makeup box is displayed within a perspex case alone, limiting any possible VOCs from affecting the larger collection.

This project was an excellent experiment in balancing the needs of an actively deteriorating modern object with its display needs. Furthermore, it was enjoyable to stretch my preventive conservation legs in a position that was heavily focussed on treatment.