Use

This was originally designed for maintaining and protecting leather slings, belts, pack straps, and other military leather products but it is perfectly suited for civilian leather gear as well. It will also make the leather somewhat water-resistant. However, it won't make your leather thong suitable for bog snorkeling. The wrapper has instructions printed in the beauty and beast of modern languages: French and German. If you don’t speak either one, here’s how you use this stuff in English.

You can use this wax in two ways depending on the condition of the leather. If it only needs a mild treatment, rub the wax onto the outside of the leather and polish vigorously with a (clean) rag. The leather should be dry before the treatment. This treatment shouldn’t color the leather. If the leather is in quite a shitty condition, rub craploads of wax on and melt it with a hairdryer. This will darken the leather to some extent and eats a helluva lot of wax. And it won't reanimate a completely dead item.