Red rot (or redrot) is a degradation process found in leather that has been vegetable tanned. It is caused when leather reaches temperatures beyond what it can handle, has been exposed to high relative humidity or from prolonged storage.
Red rot leather appears to be powdery on the surface with a felt-like consistency to the touch and a weakened structure to the leather (bends easily).
The damage caused by red rot is irreversible, but you can prevent it from spreading by using Klucel G, a leather consolidant. Klucel G is a fine, off-white powder that when mixed with isopropyl alcohol, forms a gel that is applied lightly over the red rot area of the leather. It will dry quickly, strengthening the affected area and prevent the red rot from spreading.
Once the red rot area has been treated with Klucel G, it is recommended to treat the leather with Restoration Leather Conditioner. This is a gentle conditioner formulated for treating fragile leather. It does not contain water, as water can promote further deterioration in leather. Restoration Leather Conditioner will soften the leather, help bring out the natural color and prevent further damage. It will not darken or leave the leather tacky or oily.
This type of treatment is commonly used on leather book bindings, antique leather articles (luggage, gun holsters, saddle bags, etc.) saddles, tack and other leather items.