I know I posted something similar not too long ago.
Theres plenty of stuff around to clean a pan out after cooking. Obviously a non-stick one reduces the amount of oil/fat that you are likely to use in the first place. If you are cooking over an open fire, you can drizzle any remaining oil/fat into the fire to burn off, taking much care about splashing and flare-ups etc. Grass, hay even a handfull of weeds (no poisonous ones) can then mop out the remainder and be burnt off.
When not using an open fire, the fat soaked grass can be burried or carried out. If you use something like lard that will solidify, you can keep your pan in a plastic bag and transport it around for a few days before having to clean it.
ATB
Ogri thet rog