Honestly Folks ... (Score 1)

Any component of the system (which is not sealed, and has no power applied) can just be washed with soap and water. We used to do this back in the old VT101A days. Simply remove the components (HDD must be omitted) and scrub them with dish soap under luke warm running water. A simple baking (= 125 deg.) for 20 minutes will dry everything and ensure that there is no loss from overheating. If you're too afraid to try that, the only other way to get rid of any type of system grime is 99% Isopropyl alchohol. (Definately don't use rubbing alch.) Good luck with your problem.