Unfortunately I've ended up just binning at least two cabs over the years, tho I did mostly re use the speakers for other things...
I'd suggest you offer it as free to take away on your local Freecycle type thing, there's a number of similar "stuff for free" sites too..... I've acquired good stuff like that and indeed donated unwanted things that have been of use to others.
Alternatively you could knock the front off and cut 2 or 3 shelves to fit, screw em in, and it'd be a handy tool / oddments shelf unit for utility room, shed or garage..
Ps If you did the make it into the shelves thing, you might be able to ebay ( or whatever) the speaker alone a bit easier than a whole big cab ?