Kitchens – How to remove a mark from a freshly painted wood cupboard

I think your best bet is to just paint over it/re-paint the wall. On exterior concrete/brick walls it is easy to power wash or sandblast it - the goal is to remove everything. However neither of these will work inside - aside from the mess they'd create, they'd probably take more then just the paint off your walls!

You might find some chemicals to help remove it, but because spray paint is paint afterall, you will undoubtedly damage the paint underneeth it. Permanent Markers can often be removed with Isopropyl alcohol if the markings are relatively new - you might have some luck with this on the spray paint too. However, with markers, generally speaking, the longer you leave it, the more difficult it is to remove.

By the time you get this stuff off, fix the wall, re-paint the parts that need it, you'd probably would have spent more time then just repainting.

Use a 5-in-1 painter's tool (e.g. Richard brand) to scrape them off. These tools have an edge that is slightly curved and rounded so that you can scrape without gouging a surface. I've used this for removing burnt-on gunk from a frying pan, without damaging the pan.

You may find that the paint does not actually adhere to the varnish very well and the droplets just pop off, which is the ideal situation. If they adhere stubbornly, you may nevertheless be able to use the tool to plane them flat, reducing these droplets of dry paint into essentially thin white stains. The remainder of the work can be done by a some light sanding with fine paper that won't cut through the varnish. Or, some solvent may be able to help with this last step. Acetone is almost certainly too strong for the varnish, but try isopropyl alcohol is a possibility.