Well, I found out that washable paint/marker doesn't always mean washable. Even after rinsing and soaking and spraying with OxyClean, some of her shirts still have marks on them. So, I wanted to get her some kind of paint smock. They don't really make paint smocks for tiny 1.5 year-olds, so I went to our new Goodwill to see if I could find a large long-sleeved shirt.
I ended up finding a long-sleeved, button-down shirt in size 3T. It was big enough to fit over whatever clothes she has on, but not long enough to cover her legs (she also likes drawing on her pants.) Then I spotted a sundress, also size 3T, so I got that to cover her legs. Bonus -- they were both brown, so stains will not show as much!
This is what the dress looked like. Originally, I thought I would just cut off the top of the dress and have her wear it as a skirt, and then just put the shirt on. But, I really need to practice sewing, so I decided to try to put the two together to make a full-length smock.
It killed me to cut this dress up, by the way. It was so cute! But it was too perfect for what I needed, so now Claire just has a super-cute paint smock.