I've had that problem - the spray on and wipe off polish is a nightmare. It will fade with time but using a back bumper polish will help. Don't use the silicone spray on stuff - get one that is actually coloured like your trim (either grey dark grey or black - most cars come under dark grey!
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Washing up liquid is also good at stripping off wax so you might also want to try that! (Dont scratch it off though or you will permenantly damage it!)