Should I spray contact cleaner into my equipment?

If it’s a premium product that won’t leave a sticky residue and you know how to pre-clean, how much to spray where and where not, sure.

If not, it’s best to leave this aspect of service to someone who understands the subtleties of the process. Some of the most problematic gear I come across has been doused in cheap contact cleaners that leave a nasty, sticky residue. This residue fouls switches, potentiometers and must be completely removed with a specialised cleaning process to restore control functionality.

I’ve even had gear delivered to me that has been soaked in WD40! Don’t EVER do this and if this sounds like even a remotely good idea to you, DO NOT remove the cover of your equipment or go anywhere near the WD-40!