On Wednesday, 24 June 2020 17:51:19 UTC+1, Scott wrote:
I dropped a tin of paint this afternoon. Fortunately this occurred
outside. The paint is oil-based primer (red oxide). The surface is
some sort of concrete. How am I supposed to remove this?

1. B&Q suggest white spirit but I cannot see this working after the
paint has dried.

2. Steel brush attached to power drill?

3. Nitromors?

4. My favourite - flame thrower (as used for clearing weeds)?

Is this a nice smooth concrete - maybe even polished to a glass-like finish? Or rough like many drives and roads - purposely made to stop them being too slippery?

If it is rough, you don't stand a chance of removing the paint. And any attempt might end up worse than it currently is. I agree with those who suggest painting over it.