If they're oily or tarred, throw 'em in the dishwasher. Energy saver drying cycle.
If they're dust-filthy, skate on (someone else's? welcome mat?) carpet.
If they're sort of nibbled-at looking or cracked, there's no help really. rotate and replace, don't store in high heat/ozone.
If they're sort of worn away on the inside (conical), rotate and replace. Check edging, use more grass & step stops instead of T-stops.
If they're sort of sliding out from under the skater like might happen on wet asphalt, check durometer and set-down position. Shorten stride and center chin knee skate.
until more details available?