my extractor blasts them out too.
you can also try salteraser. it works pretty good, but if your extractor didnt touch them, im not sure salteraser will help.
gelcoat almost really calls for wool pads and a rotary polisher. especially when it is chalky. that is the gel oxidation.
i always use aquabuff 1000 and 2000 with a wool pad on my makita for gelcoat.
with the 3401, another pad alternative to Mike's suggestion is the tufbuf wool pads. they...
I’m no mathematician, or a genius for that matter, but does one fluid ounce not weigh one ounce?
I’m thinking of the "what’s heavier, an ounce of feathers or an ounce of lead" adage.