Painters can be very particular about their palettes. For oil painting, I like to use a wooden arm palette. I’ve found that the best preparation is a method traditionally used in woodworking called French polishing. This method provides a tough, smooth surface that is not soluble in oil, turps, mineral spirits, or any of the other solvents used in oil painting. It’s easy to clean. Hardened oil paint, if necessary, can be quickly removed with a green kitchen scrubee pad soaked in turps or mineral spirits. The paint sticks well to the palette without resisting the brush or the palette knife.
Get yourself a new wooden palette and sand down any splinters or imperfections. Make sure it fits your hand well. You will need some fresh shellac; the stuff you get at a furniture store will do. You could also make your own by dissolving dry shellac flakes in denatured alcohol. You will need some denatured alcohol for cleaning up, a one-foot square of lint-free cloth, preferably linen, and a small amount of linseed oil. Fold the cloth into a convenient size—about 2” is good. Dip the pad in shellac and wipe it over the surface of the palette, covering thoroughly and evenly. Pour a small amount of linseed oil onto the surface of your cloth. While the shellac is still tacky, rub the cloth over the surface of the palette in a circular motion. With a little practice, you get a sense of how to do this so that the shellac is spread smoothly and pressed into the wood. Let the palette dry enough so that the shellac is it no longer tacky (15 minutes or so). Apply and then polish another layer, and another, and another, until the palette has a surface that feels sufficiently thick (I apply about 8–10 layers). It is beautifully smooth.
If the surface of your palette eventually gets damaged by repeated scraping, you can remove the old shellac with denatured alcohol and apply a new French polish. In three years of heavy use, I haven’t yet had to do that.