fabrics (such as those used in cars) cannot be dyed after they are in a car. Getting synthetics to adsorb color is not a trivial matter. The only solution to "restore" color uniformity to plastics (vinyl) and "plastic" fibers, is to paint them. Duplicolor has "fabric" paints for this pupose, that can be used in headliners, fabrics and smooth panels. Unsure how painting the terrycloth will trun out.