For the best results, the door should be taken back to its bare timber or as close to it as possible. Any flaky varnish or paint must be removed. Please see our guide “How to Strip Paint” for help with this.
If there are any deep scratches, holes or pieces of moulding missing, fill them with a plastic wood filler in a matching colour.
Then rub down the surface with fine sandpaper, working with the wood grain.