Removing grout / adhesive.

[kimmy_5]

Hi There!! Recently me and my boyfriend laid some slate look tiles in our kitchen and thought we'd washed off the adhesive properly however its developed a thinnish kind of skin over the top of the tiles making them look dirty. We want them to look nice and polished as they did when we were putting them down but am finding the adhesive a real pain to get off even with some tough elbow grease does anyone have any ideas as to what products we can use to get this off??? Many thanks in advance.