Re: Its amazing what a can of carb cleaner will do...
It certainly doesn't hurt to carry a spare filter. Adding an in-line just before the carb can catch lots of stuff that you wouldn't think gets through either.
A trick that may someday save you miles of walking: Since off roading is dirty and dusty by nature, someday the carb will get a little piece of grit, even a drop of water, in the wrong place, making it run terrible.
Air cleaner off, rev it to mid RPM as best you can, maybe 3000 RPM. Choke the carb off completely with your hand or a clean rag. Choke it off till it dies. It will be hard to re-start as it's flooded badly, Hold the go pedal down to the floor without pumping and crank away.
Sometimes it takes 2 or 3 tries to work.
What happens when you choke it off like that the extreme vacuum from the spinning engine pulls all the trash out of the passages, possibly freeing it up again. (About the same idea as putting your nose on a vacuum cleaner hose - no more plugged sinuses.)
It does not get the trash out of the bowl, and it's not a substitute for cleaning and rebuilding, but it's a good trail fix.
I've heard it called a "Mexican tune up" because it's common in Baja.