We've already used them for painting our Snowy Day pictures and they worked great. They rinse out easily when used as paint brushes too.
The other day I saw the box still sitting in the corner of our office with about 100 of these little gems left. I wondered how they would work as erasers for our dry erase boards. They work perfectly. The best part is there is NO reason for the kids to get their hands dirty with the ink. Now each kid has their own eraser during group time on the rug.