How to clean grey coloured rubber car mats?

Have tried soapy water and a little jiff, but to no avail. before somone suggests buying new ones, thay are the bloke afacturs ones and are expensive
Answer
Go to your local auto store and ask hem for a spray can with a scrubber on it that cleans your car seat floor, etc. or you can buy a soft scrubber at walmart or something and then by armor all spray and scrub it dry, then wipe it down nice with a bath towel.