What year is it?
Your best bet, since I don't know where you live, is detail the heck out of it and place an add on local CL/newspaper at a price you want and see if anyone bites. Ideally wait till "spring" or convertible season is about to begin and hope for one of those "we just want a convertible now" type buyers.
Selling it here or on RL will bring out the cheapos and those looking for bargins and more
Could be up to 30K depending on the buyer. private sale only. Wholesale /trade in prices will only depress you more.