My wife and I have an agreement: I get gadgets and she gets jewelry. Very simple.
So here's a great one. Get an Ultra-sonic cleaner. I got one from Jaycar. They are about $100. Tell her you got it so that you can clean all her jewelry. It does a bang up job!
Works great for cleaning RC parts, bearings, drive parts, etc.
My wife calls ours the "flux capacitor"