Try cutting small slits in the decal with a new blade. Coat decal with Microset and allow it to soak in. If that doesn't loosen the decal, go for broke and try Solva-set. To avoid re-occurence, always lightly blot the newly installed decal to get rid of excess water. Check your newly-installed decals about 30 minutes after you put them in place. Correct any slippages them, before the decal dries completely.