Need to look that up >> Decorative only, not for food surfaces, according to the Sharpie company. If you want them to permanent, increase oven temp to 425 and let them cool in the oven. I've put mine through the dishwasher with no probs.
Button trees...Love This might make a good art project for Mother's Day? Or seasonal changes - 4 small squares where the kids paint trees use different colored buttons to represent each season then put all quarters on a larger sheet together????