No there is not much you can do, things to consider does it already have a sealer coating on there if so no cleaning will help, it needs to be stripped first than cleaned than a wet look sealer applied. If there is no coating on the tiles than a good alkaline tile cleaner is what you will need to use than rinse the floor with clean water afterwards..
Craig
Im not sure about the sealer coating, but what sticks to my foot in the bathroom appears to be very thin layers of clear stuff+ some slate. if that indicates that it has been sealed, then how do I get it stripped? is that a DIY job?