Is there a way i can safely clean my keyboard without using compressed air?

[2x3i5x]

should a keyboard cover be used?

[soybean]

should a keyboard cover be used?

Do you mean putting a simple cover on the keyboard when it's not being used or a cover that's formed to be a permanent cover and left on during use?  I've seen the latter in car repair shops where workers with dirty hands need to use a keyboard.  Without those covers, those keyboards would probably not survive very long.

[2x3i5x]

http://www.compucover.com/

[musicworld1]

you can clean it by the pump that is used for bicycle.

[JJ 3000]

Hmm..
I've never considered that option before. Seems like it  would have to be a two man operation - one pumping while the other holds the hose.