I recently painted the trim in one room of our house with high gloss oil based white paint. I think the paint was old and had yellowed somewhat. Now that the room is completely finished and expensive wall paper installed, I realize that I am unhappy with my high gloss "yellow" trim. I asked my local paint store about de-glossing before painting over the trim. They said it was unnecessary and I could simply paint over the existing high gloss paint. I always thought it must be-glossed before painting over high gloss finishes. Does anyone have any ideas on how I should proceed? I would like to paint over with a semi-gloss or gloss paint.