Rubber makes pretty good tinder. Once it catches it burns hot and for a considerable time considering its weight and bulk. Of the rubber tinder tried the best so far is the wrappings around the core of an old golf ball. It is very fine bands that catch easily. Another recycling tip I guess.

First I heard of rubber as tinder was pulling a few strands of elastic out of your jockey shorts or socks to use as tinder. Bet you never considered that. A survival instructor I knew was big into using what you wear. His thought was that virtually everyone has a considerable amount of gear always on hand if they just knew about it.

Of course burning rubber gives off a nasty smell, toxic fumes and produces a lot of soot that pollutes anything placed over the fire. At least it does until the rubber burns off. And don't be surprised if hours after you think all the rubber is burned off little bits of it flare up and stink. An acceptable trade-off in a survival situation I figure. In small amounts it might be acceptable for wider use. Give it a go and see how it works for you.

Another option to try is latex foam rubber. Preferably the stuff not treated with a flame retardent.