On the inner surface of the glove box door on all coupes and cabriolets built after 1956 are three elastic bands (date not certain, VINs 56175, 56472 and 56836 do not have the upholstered panel or elastic bands). When the cars were first purchased, the bands served to secure three items: a small plastic bottle of glycerin, a package of fuses, and usually a plastic document pouch.
The glycerin bottle was placed so that the top was "up" when the door was closed. It is sometimes mistakenly stated that the glycerin was intended to be used on the rubber door and trunk seals to keep them soft and pliable. While it may have functioned effectively in that application, in fact the small paper booklet that came attached to the glycerin bottle makes clear that its intended purpose was to keep water from freezing in the door lock tumblers, serving as a form of anti-freeze and a inhibiting corrosion, as the lock tumblers are brass. One drop on the key and inserted into the lock was all you were asked to do.
The text of the booklet reads as follows (photos below):
Dear Customer: Though your Porsche's door lock resists the entry of water, the danger of condensation water is still imminent with sub-zero weather. Therefore, to prevent it from freezing fast, inject liguid of attached spray-bottle into key slot, operate both key and knob, and clean lock and vicinity thereafter.
Do not mix or confound with food! Not dangerous when got into touch with the skin, even if slight injuries occur!
Apparently the translator was not a native English speaker. One can only surmise that the last sentence means to say that if one has a cut in their skin, the glycerin will not cause a health problem.
This booklet, part number W 33 3M 4.59 Gl, was the smallest piece of Porsche produced literature. All of the literature peices that have actually been documented were dated 4-59, so apparently the glycerin bottles were not provided before that date [anyone with evidence to the contrary, please contact Barry using the email link at the bottom of this page]. The bottles had black caps for cars prior to about '61, red caps thru '65, and maroon for 900 series cars up to '67 or so. Most of these bottles were discarded or lost in the storage pockets.
The document pouch was clear plastic, about 3 1/2" X 3", which typically contained a card with the dealer information and was for inserting your registration and other papers into.
The photos below show the glycerin bottle booklet and instructions.