I would disagree with the first video as I believe there's an easier way. Grab some new plastic boom sleeves that adorn new booms from your local shop. Strip all the hardware from your boom. Then tape the covers in position and pour about a cup of thinners (enamel or acrylic) down into the gap between the old boom and new cover. One side at a time works best. Turn the boom upside down each couple of minutes or so, making sure that the old grip is fairly saturated. After about 20m or so the old grip will virtually slide off. I use some old work gloves to help stripping which makes the job really easier and cleaner. Then a bit of a clean up with acetone should see the job right. (about now is a bad time to light up a smoke too) The acetone should make the glue bond well to the newly stripped boom..
Or you can buy two rolls of the one inch wide elastoplast at Coles for around 18 dollars and regrip the boom that way. It's more tacky than standard grip.
Mark at Surf Sail (West Leederville) has multiple types of grip rolls. I have just used one of the Goya replacement rolls - feels sweeeeeet and looks schmick.
