a couple things the vid did wrong... you should never scrape one side of a ski at a time you should always scrape the whole thing at once, so ur base stays even. also brushes not needed of ur racer yes for general skiing and park u will never see the difference so not worth ur time .. another thing i would never go that slow with the iron on a ski its better to go faster and make more passes on a ski than to go slow. older skis the glue will brake down and if u heat it that much it will let go and u will bubble the base and ur fucked. and last never gummy stone ur edge yeah it will take out burrs and rust but it dulls the edge...edges are the one things thats kinda hard to do u can really mess a ski up if you dont know what ur doing..
as for me i raced for ten years and have been to almost a dozen ski tuning sessions with people who work on the us ski teams skis
so long story short wax scrape shred all the other stuff is just a waste of money
just rember that the people who raced will always be better well rounded skiers then the people who hate on them