i think you should disassemble it completely. it' quite easy and you need only phillips head screwdriver and torx T5 (or was it T6) key. then clean it up (you may have to use some rubbing alcohol to get the dryed beer out of components.) assemble it and try it out.
I painted my N900 and disassembling it was wery easy, just think and look before trying to pull something apart
pity though, heineken is such a good broduct. so is n900...