Improper storage can cause mold to grow on leather surfaces. Leather develops a whitish coating, blackish spots or smells unpleasant due to improper storage. In most cases it's mold.

LEATHER CLOTHING

Surface level cleaning. ensures the majority of the mold is not visible but it doesn't completely remove mold from the clothing. Therefore, just cleaning the surface is not sufficient. We recommend washing the leather garments with a suitable detergent. Garments may require pre-treatment with a dedicated product that prevents colour bleed. If the smell is strong, bear in mind the smell can't be completely eliminated. Important: After washing and treating do not store the clothing again in a bag or in a humid environment without air circulation. This will cause the mold to re-appear.  

CAR UPHOLSTERY AND LEATHER FURNITURE

The following instruction is for pigmented leather (coloured finish on the surface). In case of other types of leather, always contact a specialist first. In particular porous leather (suede, nubuck and aniline leather) must be treated cautiously!

Leather should be stored at room temperature with humidity level of 40 to 60 percent with adequate air circulation. Air humidity above 70 percent, high temperature and lack of air circulation support the growth of fungi and bacteria.

We cannot answer comprehensively if mold can be removed with cleaning and care products alone. It largely depends on the duration the leather was exposed to adverse environmental conditions and every case has to be looked at differently. Little bit of mold that appears on vintage car seats after a few months, usually can be removed by simple means. Upholstery parts, where the mold has spread over several years, are rarely removable. The reason is not only the visible soiling on the leather. Mostly the entire inner core of the upholstery is infected with mold and the smell remains despite thorough cleaning. The mold spores are blown out together leaving an unpleasant odour.

Spraying air fresheners or other perfume to mask the smell does not solve the problem either. It only results in a mixture of perfume and mildew smell. Such severe cases can only be solved by replacing upholstery and leather by a re-upholsterer.

To clean light mold growth follow the procedure below: Clean all leather surfaces with Geist. Rapid Cleaner PRO. Most of the mold is invisible and hence, it is best to clean the entire surface thoroughly to remove all mold spores as much as possible. This includes frame, feet (furniture), but also the entire interior such as interior roof, panels, carpets, etc. (cars).

Several products for general mold killing have been tested but vinegar essence and isopropyl alcohol were found to be the best. Alcohol however, is out of question, as it can dissolve the protective layer on the leather. But vinegar essence is an ideal product. Leather is in the acidic state after the tanning process. Over time the pH levels within the leather shift causing the leather to become slightly unstable. Correcting the pH levels is therefore a recommended measure for older leather. Treating the leather with vinegar essence nourishes the leather. Mix the vinegar essence (usually twenty-five percent acetic acid) with same amount of water. Ensure all surfaces are treated with this mixture. Not just the leather. Don’t wet the area too much while working.

This treatment should also remove the smell of mold if leather had not been incorrectly stored for too long. To verify this, park the car for a while in the sun and keep the windows closed or heat the furniture in front of a sunny window or with a hair dryer. Repeat the process until no smell is noticeable. Geist. Odour Remover for leather & vinyl can be used additionally. Also, try to detect the source of the smell. Heat the surfaces and check every part. This ensures the source of the odour is treated.

Appropriate aftercare is crucial in making sure it doesn't re-appear. In particular, the use of vegetable/animal fats and oil based care products provide the perfect breeding ground for re-infestation. It is therefore important to use synthetic products for ongoing maintenance and care. Geist. Leather Conditioner and Geist. Leather Preserver are based on synthetic oils and fats to conserve leather without increasing the risk of mold. Geist. Conditioner is suitable and recommended for dull/matt leather. It contains oils that keep the leather soft and antioxidants that reduce the degradation of the leather. Geist. Preserver on the other hand is a suitable product for shiny/glossy leather and for leather stored in areas like the house shed which is exposed to environment. As it’s a wax based product, it stays more on the surface and provides better protection against mold. Both products are very intense and a regular economical application is always better than intensive treatments.

The best protection against new mold is good storage! Just using a suitable care product cannot permanently prevent mold. It is not necessary to constantly check the temperature and humidity, but clearly wrong storage locations and conditions should be avoided at all costs.