I like to run a scotch pad over my boards then wipe down with alcohol and a lint free cloth. After soldering I spray it with WD40 Electronics Cleaner and a small brush then carefully blot with a lint free cloth.
Here's a Crunch Captain Deluxe, I think could be easily modified to work, just delete the switch on the right
https://drill.taydakits.com/box-designs/new?public_key=QkZGaVR5SThsQ0ZEQVZsckZLTnhmdz09Cg==