I have a car that was "repossessed" in 2004. The bank never took possession of it and (as far as I can tell) doesn't even know it exists; since they have issued credit to me since then. I want to get rid of it. I don't want to open a can of worms. I have kept it registered and insured this whole time.

A repossessed car is one where the lender took possession of the car because of a loan default.

So I really don't understand what you mean that it was "repossessed " or that you were issued a credit.

As long as the car is currently registered without a lien against it, you should have no issue selling it.

If they hold the lien on it, you go to the bank and ask them to sign the title to you.

You go park it somewhere and let it get towed away.