Family member had a plant in a jar on the windowsill over a longer period of time and over time (i guess while watering) water spillage has made its way under the jar and made quite the damage to the sill. Is there a good way to fix such a damage? Will obviously from now on have something underneath the jars to prevent this in the future.
Scrape the raised area with a razor blade. Block sand it with 80 grit, hitting more than just the bad area.
Cover with a thin coat of wood filler, using heavy pressure to force the filler into the fibers. Once that dries, block sand again with 120 grit, then once more with 180 grit. Make sure you sand beyond the patch to blend the repair into the rest of the sill.
Thoroughly clean the dust. Apply two coats of primer to the full sill. Once dry, sand lightly using 220 grit, without a block.
Scrape, fill, prime, paint.
Scrape the raised area with a razor blade. Block sand it with 80 grit, hitting more than just the bad area.
Cover with a thin coat of wood filler, using heavy pressure to force the filler into the fibers. Once that dries, block sand again with 120 grit, then once more with 180 grit. Make sure you sand beyond the patch to blend the repair into the rest of the sill.
Thoroughly clean the dust. Apply two coats of primer to the full sill. Once dry, sand lightly using 220 grit, without a block.
Clean up any dust, then paint.
You'l have a smooth sill with no signs of damage.