Cleaning Vci 100

Hey Guys, I have a problem with a couple of buttons on my Vci, it's not that they don't work it's just that I have to push them quite hard sometimes to get them to work!. I have been on the road the last couple of years and the dust and dirt have got into the mixer does anybody know what I could clean the buttons on the circuit board with, I have just cleaned my crossfader with a non greasy solvent spray and it seems fine...would this work on the buttons or would it make them stop working altogether?.

Thanks

Brett