CANNED AIR may hurt your camera by releasing the PROPELLANT at wierd angles or if shaken up prior to use) canned air as in what you buy at a computer store

COMPRESSED AIR is what EVER repair lab uses ;) compressed air as in AIR COMPRESSOR set to a low PSI.

I used an AIR COMPRESSOR to clean my FILM bodies bi weekly for years and now my 1D (though the PSI I use is far less for my DSLR)

CRINGE if you'd like, but DO NOT EVER send your camera for repair if LOCKING UP THE MIRROR and blowing air through it scares you.

AH, I see you avatar is an older manual body...... I cleaned a few LEICAS and CONTAX RTS's this very way also ;) they still are MINT.