Linseed oil has been used as a wood preservative because of the attractive luster it imparts and its tendency to dry into a hard finish over time. Because the oil penetrates the pores of the wood, it helps maintain the wood's natural moisture levels. Unfortunately, this same characteristic makes dried linseed oil difficult to remove completely. If buildup becomes dark and unsightly or starts to support mildew growth, removal is a two-part process involving stripping and sanding.
Things You'll Need
Ethanol or acetone
Medium grit sandpaper
Fine grit sandpaper
Clean and dust the surface with a damp rag. Don gloves, eye and breathing protection. In a well-ventilated area, dip a clean rag in ethanol or acetone and apply the solvent to the linseed oil finish.
Scrub the surface with the rag, applying more solvent as needed. Acetone may cause the dissolving linseed oil to become sticky; replace the rag with a new one as needed. Continue to scrub until no more linseed oil comes off on the rag.
Sand the surface with medium grit sandpaper to remove linseed oil that has penetrated the surface of the wood. Continue until only raw wood, which is generally lighter colored, is visible.
Remove dust with a clean cloth or shop-vac. Sand the surface with fine grit sandpaper until the finish is even and smooth to the touch. Give the piece a final wipe-down and check for splinters or spots you missed.
Ethanol or acetone will also remove linseed oil from most stone surfaces. Rinse the stone thoroughly with water afterward.
Solvent-soaked rags are a fire hazard. Dispose of them in a fireproof container; don't just throw them in the trash