Well, it sounds like the abundance of life out there makes you worry. You shouldn't. 99.99% of life out there is threatened by your presence, not the other way around. The field of human pathogens is pretty clear, and you don't find them just sitting around outdoors. You find them from other people. Very few organisms have the potential to be pathogenic.

You won't get any kind of worm from moss, dirt, plants, or the air. Only a VERY few people manage to get nasty fungal infections in the wild, and they almost always live in constantly wet, hot tropical regions. Skin is a pretty darn effective barrier against pathogens. Same for bacteria - the only stuff in moss is bacteria that eats other bacteria and similar things. The wild would be the LAST place to find dangerous bacteria, as it would quickly get swarmed and eaten by bacteria more suited to the environment. Now, go digging in poop pits or not washing your hands after using the bathroom, well, you just exposed yourself to your own germs. Oops!

Cleaning pots - I'm a pretty anal guy when it comes to cleaning. I've done a lot of microbiology work and most people's kitchen practices drive me nuts, cross contamination is rampant. When it comes to pots in the field, I just clean mine (with my hands) of all visible (or feelable) debris. Bacteria on the surface of metal usually dies within a few hours, it's VERY inhospitable territory with ions and such causing all kinds of problems. Bacteria can thrive in patches of food, etc, that aren't exposed to metal however. So don't leave debris in the pot.

Scratching pots isn't a problem unless food accumulates in the scrapes - see above. It's much much more a problem with plastic as bacteria take up residence in plastic scratches. Metal will kill bacteria (coins are dirty usually, not with high bacteria counts). Plastic provides a nice, moisture retaining home for bacteria.

Bottom line, you could run around naked and roll in dirt, wipe yourself with leaves, and lick all the moss you wanted. The actual problems you'd have doing that? Mosquitoes, sunburn, getting dirty, getting poison oak, and looking like a darn fool licking a tree. You won't catch any mysterious disease or rash. Go to a city and hang out with people for that!!