Having garaged our ‘96 XJR for several years, and only taking it out for annual maintenance or occasional exercising in dry weather, we never had a need to remove the OEM floor mats. We’ve discovered that the foam rubber used to keep the floor mats from shifting around has completely decomposed, leaving a blackish residue on the cream colored carpet. It appears to perhaps reacted with the adhesive that Jaguar used to apply the foam to the back of the mats. What have people used to clean the carpets and in particular remove the black material from the carpet. We’re concerned about affecting the carpet backing Jaguar used for the car’s carpet. We’d like to know that before using any material (steam, carpet shampoo, mineral spirits, dry cleaning solvents, etc.)