Replying to Best way to reallly dull edges

yeah so this is a repost but i need legit help. whats the best way to dull factory new edges without damaging the edge? Im used to having my 4 year old skis with litterally rounded edges and now im skiing with swords and cant do anything. I could bring em to a shop but all they eve do is hit them with the machine at a 45 angle and it doesent help much. Soo whats the best way to get them reall dull without taking to much metal off? I been wondering