Friend of mine has an 8 year old set of unused R6 Hoosiers. Date code 2806. They have been in the garage in black plastic garbage bags.
Value???
Whatever the market would bear...I know some folks that will not use sets older than 11(s).
Others? They are OK. About 40% of retail is a good starting place.
I had a set of HWETs from that first run- about 2806 or something date code. hard as rocks and I had better luck on dry tires with fresh rubber.
Unless they were stored in climate controlled area, I'm not sure I'd bother doing anything with them except tire swings.
sorry- tried the cheap old tire route and it didn't work well.