To elaborate a little more on what maxpower said,
To get rid of "silvering" on your model is to let the decal dry completely, then re-apply the solvent making sure to cover the edges very well....you will see the "silvering" or air under the decal very well after it is wet again...then, carefully poke a few holes in the decal using a SHARP hobby knife. The solvent should bleed through the holes and you will see the "silvering" slowly disappear. You may have to repeat this a few times until the decal looks clear.
You may also have to cut the decal on seams, or other raised details to get it to lay completely flat, but if your using a good decal solvent (and decal), a small hole to let the air out will usually work.
Happy Modeling !
Jerry