From experience, if you absolutely have to sell something musical, sell amplification, mikes and "gear" - these are easier to replace when times get better without such a sense of loss (most of this sort of gear is mass-produced and doesn't mature with age) and also easier to borrow if, for example, you do some playing for a church group and then ask to borrow the amplification for a non-church gig.

If you have time on your hands, busking always helps. It reconnects you with why you play, what you play and the effect you have on the one man and his dog who actually stop and listen. Additional income is incidental but welcome.