Leather liners and
chinstraps often deteriorate because of poor storage or improper
attempts at 'preserving' the leather with saddle soap or leather oil.
In fact, most of the damage found on leather is caused by improper
treatment by someone who acquired the helmet after the war. Leather
deterioration is a common problem and there are a few things a
collector should know before attempting to treat a given helmet.
'Dry rot' is a condition
where leather is essentially rotting from the inside out while it
maintains a dry or hardened appearance. Under these conditions, the
leather eventually reaches a condition resembling the overall
consistency of dry cardboard. Leather that has dry rot breaks apart,
tears and crumbles easily, and can turn into a fine powder if stress
is placed on any part of the surface. Dry rot occurs in leather that
has been improperly stored in hot or dry environments. Essentially,
dry rot results when the natural oils in the leather have been
depleted over time. Once dry rot begins, it can not be stopped. A
leather liner or chinstrap with dry rot will eventually deteriorate
until it is hard, cracked, and broken.
Dry Rot is caused by:
Improper storage in hot or dry
conditions (attics, sheds, and garages).
The application of leather balms,
salves, creams, or soaps intended to soften or clean the leather.
A depletion of natural oils in the
'Wet Rot' is a condition
where the leather possesses too much moisture. As a result, fungus,
mold, and mildew infest the leather and cause it to actively
deteriorate. Wet rot occurs as a result of improper storage in wet or
humid environments. Leather with wet rot will turn dark brown with
green or gray mildew inside and out.
Wet Rot is caused by:
Improper storage in wet and humid
environments (basements or damp cellars).
The application of gun, machine,
automotive, and leather preserving oils.
Active bacteria that are attracted to
the leather by moist or wet conditions.
Under most conditions, dry rot can not be reversed once it begins. On
the other hand, wet rot can be reduced if the helmet is removed from
the moist environment where the fungus is growing. In either case a
helmet left to these conditions will soon be left without its liner
and chinstrap. In most cases, it only takes five to ten years for the
leather to deteriorate fully under these conditions. While wet rot is
easily prevented by simply removing the helmet and placing it in a
more suitable and stable climate with less moisture, dry rot continues
to be the culprit of most leather deterioration.