If you haven't used it in 10 years you clearly aren't going to miss it. Put it up for sale with the switch problem noted, for a reduced price. The new buyer will likely try to clean the switch themselves using a product like Deoxit. Since you don't know if that will solve the problem be sure to deduct enough to share the risk, if it must get fixed a pro.
For prices you can use Audiogon's Blue Book which costs a little money or look at completed sales of similar products on Ebay. Don't assume the asking prices are meaningful.
For prices you can use Audiogon's Blue Book which costs a little money or look at completed sales of similar products on Ebay. Don't assume the asking prices are meaningful.