You should, since what you doing is basically a controlled melting. You don't want it to go crazy on you. Just remember to make sure the decal is where you want it, no going back once the Micro-solve is on. Even the bristles of a very soft brush will make life un-fun.........unless, your intention is to distress the decal. Just think it through before you do it maybe just make up a small bit of zim out of putty on some scrap and use a decal you don't want or need to practice.

Don