Air filter cleaning?

Is it one of those cotton gauze filters? Like a K&N automotive filter? If so, then yes. Rinse it off in the kitchen sink. Work from the inside out. That way the dirt comes out of the filter rather than being pushed deeper into it. You shouldn't need to oil the filter. The bike will take care of that for you.

I use a little dish soap and wash mine in a coffee can. About once a month, more if I do a lot of off-road dusty trails.