nothing wrong with the DA and coarse paper, but I think the mop and wire brushes [especially] are faster and last longer ... called a mop disc cuz that's what it sez on the label

some call them flap discs, but I think 'flap' really applies to the wheel type
speakin of spendy, and Woody's Wagner, I noticed at the tool place this morning that they had a 7" depressed center wheel that had the same coarse 3M kinda stuff as that Wagner disc - thought about trying it until I realized why I never had - the mop disc was $15, the 'stripper' disc was $25
and Builder - heat and a chisel is fine if you've only got a patch or 2 to remove, but pretty slow doing a lot, and like our Joker is fond of saying, time is money

Bill