So not helpful.
Next stop, Google. Which leads me here. Which has about a million things to try, from rubbing alcohol to hairspray to acetone nail polish remover. Eventually I decide to try the things they suggest that I actually have in the house, and achieve a happy ending thusly:
- Wet stain and scrub in liquid detergent with an old toothbrush. Rinse. Repeat until this is doing no more good. (Smears at edge of paint spot are now gone.)
- Squeeze out excess water. Pour acetone nail polish remover over stain and scrub with toothbrush. Rinse. Repeat this until it's doing no more good. (Brightness of paint spot is now gone, leaving dull/faded impressions.)
- Squeeze out excess water and apply acetone as before. Scrub with a green steel-wool scrubby pad. At this point, tiny crumbs of paint can be seen leaving the area. Rinse. Repeat until paint spot is gone.
- Repeate toothbrush-and-detergent step. Rinse thoroughly. All that acetone can't be good for your jeans.
- Toss 'em in the washing machine.