The following is suggested, but not to be considered the only right way to remove decals from window glass.
STEP 1: Wet glass with soapy warm water via strip washer or sea sponge.
STEP 2: Use a professional grade glass scraper, with new, clean, stainless steel blade to scrap under and remove decal. Test scraper in a inconspicuous area of glass first to see if razor blade use will not damage glass. This is needed because, every pane of glass is different; some may have fabricating debris and some may have a coated surface. Read FWCT’s article of the hazards of glass fines/ fabricating debris for more info. Generally, you can not use a razor blade on glass with fines but, in some cases you can lightly use a razor on coated – tinted surfaces.
STEP 3: After decal has been removed, use a “degreaser” like Oil Flo, to remove glue left behind from decal. Apply Oil Flo with a clean, soft cloth and rub onto decal residue until glue dissolves.
Again, follow the manufacture’s recommendations for use when using chemicals like degreasing agents. Acid resistant rubber gloves and safety goggles may be needed. Oil Flo and other degreasers can not be used on coated surfaces because the chemical can’t tell the difference between glue and the tinting and will dissolve both!
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Degreaser’s will work on windows with glass fines. Glass fines are commonly found on “tempered glass”. Tempered glass is glass usually located in high traffic areas, i.e… Store front windows and glass doors. The tempering process makes the glass 10 times stronger than regular annealed window glass, and is the reason tempered glass is used in locations where impact from people and other objects are common. If this is the scenario you are looking at, skip the razor blading and apply the degreaser directly to the decal to loosen. It should loosen and allow you to peel off the decal by hand.
STEP 4: Finish by cleaning glass with the standard window cleaning procedure, (Strip wash to apply soapy water, squeegee rinse).
If you’d like more information on how to restore glass by using professional window cleaning techniques to remove paint, caulking, decals, stickers, hardwater spots, oxidization and more… Please click here.