Just dont go to those "park n sell " or " consignment " place .. at the end of the day .. your car will be NOT SOLD, and with extra km on it .. and u need to pay ...
If your car is a nice car, it will be the JOY ride for them on the weekend .. FREE !
major dealers will take a big cut of depreciation. Only give u book price, probably 1/2 of what you will get in open market.
if u have money to spare why not, let them do the dirty work.