I have seen this pinned many many times on Pinterest (including pinning it myself!). It sounds so easy and awesome. The only problem I’ve read over and over is that regular Sharpies will come right off after you wash the mug/cup. All the sites recommend hand washing, but that would never happen around here- if we have to hand wash it, it doesn’t ever get used! (and I am sure I am not alone there!) I did read in a few comments that people have had much better luck with the oil based Sharpie Paint Pens. I always have the kids make something for the grandparents for Christmas and I knew this would be perfect.
Since I wanted something the grandparents could actually use every day, I went with coffee mugs and tumbler cups so we could color the outside and not have to worry about the paint pens being food safe or not. If you choose a plate, I probably would advise not eating off of it and use it for decoration only :). I found the mugs and tumbler cups at Ikea of all places- the mugs were $2.99 each and the tumblers were $1.99 each. Score! (You can also find cheap mugs, cups, plates, etc. at dollar stores and thrift stores!) I got the paint pens all shaken up and ready to go for the kids and let them use their imaginations to color all the cups. My oldest definitely had the most fun with it. I had to help the other two along and they lost interest quickly :).
Once you’re finished with all your decorating, set them on a baking sheet and allow them to dry for at least 24 hours. Once 24 hours has passed place them in a cold oven (this is important! you want them to heat up with the oven). Turn the oven to 400 degrees and set a timer for 40 minutes. After the 40 minutes is up, turn the oven off and leave the cups to cool with the oven. Once they’re cool they’re ready to use! The colors didn’t stay as bright as I would have liked but they still turned out awesome, all the grandparents loved them. My mom even washed their coffee mugs in the dishwasher on the sanitize cycle (extra hot!!) and they came out just like they had gone in. Happy crafting!