What kind of pencil do I need?

a sharpie

I have used Sharpie's oil based markers with great success. I put them in a cold oven after writing, turn the oven on to 350, leave them on for half an hour after they reach 350, and then turn the oven off and let them cool until completely cold. You can then take them out and they're washable by hand. I have never tried to put them in a dishwasher so I can't tell you how that would work. Pretty durable so far.

You can use regular permanent markers and bake in oven as above. It works great. Then just for safety I've used Elmer's glue diluted over the painted area.

China marker

A plain Sharpie will come off in the first wash. Make sure to use OIL BASED Sharpie. Look for Paint Pens or your work will be wasted. Happy Crafting!

Need to use an oil based marker-Wipe off the surface with alcohol to clean it, put whatever you want to write on the mug and let it dry for 24 hours then put it in a cold oven, set it to 425 degrees. When the oven gets to the right temp then set your timer for 30 min. When the timer goes off turn off the oven but leave the mug inside to cool off inside the oven. By putting the mug in the cold oven it will not crack. Got all this off of Pinterest when I did it and it worked. Have run my mugs through the dishwasher many times without the markings coming off. Good luck!

I started with Michael's but went through art supply sites and Amazon for sites. They also have more color options