Concrete Paint Help Needed Please.

[MyBlackHen]

My neighbour painted his new garage floor with concrete paint to keep the dust down. Very sensible.

He had a good amount left, so decided he would paint the top half of his (tamped concrete) drive with the rest.
Well, the sun and the frost have lifted most of it, so he decided it would have to go. Him and my OH jetted it with a pressure washer, and got 90% of it off, however there are two patches. that are sheltered, and don't get the baking sun. He has wire brushed those areas this afternoon, and tried a paint remover to no avail.
I said I would ask for any advice in here, thanks in advance.

[The Builder]

The easiest way would be to fix a sandblasting attachment to the pressure washer. That'll clean it up.

Otherwise, an electric drill with a wire wheel (like a circular wire brush), or one of these in it.....

http://www.screwfix.com/p/surface-preparation-wheel-with-arbor-100mm/31074

[MyBlackHen]

Many thanks for that Builder, I will pass that on to my neighbour in the morning.