A few words, since summer is upon us...

If your tin of Proofide has spent several days in transit in warm weather before arriving at your door, the contents may have softened or even liquified. If the container is warm to the touch, you may have a mess opening it right away. I'd suggest setting the warm tin upright for a bit to allow the contents to level,...and then let the tin cool to indoor temp prior to opening.

Keep the tin indoors. The natural ingredients will last longer without turning rancid if kept cool. You may even store it in the fridge (or freezer, per Brooks!). A std 40g tin is a large supply that will treat a saddle for many years.

FWIW, I treat the underside. It's very dry here in the desert, and I don't want the saddle to prematurely age and tear at the rivets. Initially, a generous but not wasteful amount is applied to every bit of surface I can reach with my fingertips; afterward, it's "as needed," maybe after two years or so. The topside gets a light treatment every 4-5 mos. It's greasy stuff, and a little goes a long way.