Removing old vinyl lettering can be a challenge but here are a few tips. Begin by softening the area you’re working on with the aid of a heat gun, being careful not to apply too much heat or for too long. An X Acto knife with a flat #17 blade, or the wider #18, helps. Don’t push down with the blade or you may scratch the substrate. Just gently ease the tip of the blade under an edge of the old lettering and lift.
But once the lettering is removed, you’re only half done. Next comes what can be the messy task of removing the old adhesive. There are several adhesive removers on the market, but if you’ve used some of them, you’ve likely found out that many just make a big sticky mess.
So here’s my formula for an adhesive remover that really works. In a small container that you’ve labeled as such, mix a small amount in a 50-50 solution of mineral spirits and isopropyl alcohol. With a rag, lightly dampen the old adhesive and give it about 30 seconds to soak in. Then with a dry rag, simply erase the old adhesive. This may take a couple of repeats to get it all. The mineral spirits loosens the adhesive and the isopropyl alcohol keeps it from being a snotty mess.
Once you’ve got it all cleaned off, wipe the area with just the isopropyl alcohol to remove any traces of the mineral spirits.