For WHM's Teacher Appreciation Gifts, I used a spray-can of chalkboard paint to paint the flowerpots, and then hand-painted the yellow "rulers" at the tops of the pots. Despite my normally steady hand, I managed to go a little off track in one area.
I sure wasn't going to tape off an entire flowerpot to fix the black, but what to do?
Here's what to do when you need to touch up a small area that you've painted with spraypaint:
First, put on a rubber glove on your spraypainting hand, and/or take off your rings, etc.
Second, get yourself a Ziploc baggie. I used sandwich size, but it would work if it were larger.
Third, open the bag and put it over the spray can.
Now tilt the whole thing down as though you're getting ready to spray something, but spray into the bag for a good solid three or four seconds. (Be sure to angle down, or the paint will drip right out!)
The paint will wet the inside of the bag, giving you just enough to dab a brush in there and get enough paint to do your touch-up work, without having to tape off the entire project and risk getting stray spray ruining whatever wonderful work you've already done. The rubber glove protects your hand from being covered in paint. And when you're done with the touch-up, the glove and bag get tossed in the trash and you've made absolutely no mess at all.
I hope if you ever need this, it works as great for you as it does for me! I've used this little trick a few times now, and it always makes me happy to get just the touch of spray paint I needed without all the extra work.