I can relate on this. I have bunch of worthless token on my stash, some were from bounty and some from an exchange where it loses its value overtime until it was delisted.
That's what happens when the token doesn't really worth something. Once the exchange finds out that there's no actual volume for that token, they will dispose it.
I think there is none but just lay it there, if your garbage token is too many I would follow what eagleman said, create another erc20 address for your valuable token.
There's no other choice unless Vitalik will do something for this.
I guess OP means selling them but obviously they're worthless is the project was discontinued or scam.
If he just wants to get rid of the tokens he can also just send them to another address but for me that wouldn't be worth the effort and tx-fee.
Selling them is useless, no market, no value, no buyer. Sending it to another wallet address is also a choice for him but I wouldn't spend gas with that.