I keep a clean shop towel with me all the time, replace it when it starts to get messy (goes in the dirty job pile next), and sort of reflexively clean as I go or as I spill. When I am thinking about what to do next, chances are good I'm going over whatever tool I last used with the shop towel.
I've got two shop towels and a small pile of new to me tools next to the PC right now, and every once in a while I pick one up and mess with it while I read posts.
WD40 evaporates, I have a tray I drain the dregs of quarts of oil into, and just use that. Sometimes I use Marvel Mystery oil since it has that wintergreen smell.
I can't really picture myself actually polishing a tool though, just getting the crud off.