Varnishing over stickers will seal them on the wood, making their presence practically permanent. After varnishing, you cannot remove the stickers unless you first remove the varnish. This allows you to creatively change the look of the surface to fit your tastes and needs. If, however, the stickers are unwanted, you should remove them from the wood surface before applying the varnish.
Several methods will remove the stickers without damaging the surface. One method is to apply heat from a hairdryer set on low to the sticker. The heat will soften the adhesive, allowing you to gently pull the sticker off the surface. Another option is to saturate the sticker with rubbing alcohol before gently scraping it off the surface with the dull side of a butter knife. If a sticky residue remains after removing the sticker, wipe the surface with white vinegar. White vinegar will safely remove the stickiness.
Applying varnish over stickers will seal them in the wood surface for years to come. To start the process, wipe the entire area where you will be applying the varnish -- including over the sticker -- with a damp cloth. This will remove dust and dirt from the surface. Wait until the wood surface is dry before continuing with the process. Carefully paint the varnish over the sticker with a clean paintbrush, using smooth, even strokes. Once you have the sticker covered with a light layer of varnish, let the surface dry for 30 minutes to an hour. If you can still feel the edges of the stickers, apply another thin layer of varnish. Keep applying one layer of varnish at a time -- allowing each layer to dry before applying the next one -- until you can no longer feel the edges of the sticker.
Matte or Gloss Varnish
Both matte and gloss varnishes work well for sealing stickers on the surface, and the one you choose depends heavily on your personal preferences. Matte varnishes give the sticker a dull finish that has no shine whatsoever. A gloss or glossy varnish leaves a shine on the surface it covers, including the sticker.
Ventilate the fumes produced by the varnish by opening doors and windows and running a fan. Furthermore, never use varnish without first reading the directions and warnings for the type of varnish you are using. For best results, follow the instructions and warnings that are printed on the varnish's label.