How to deal with a coworker with terrible handwriting?

A coworker at my summer job is really nice and a good worker, but she has absolutely horrible handwriting. We do a fair amount of writing here at the store, and sometimes certain business transactions are made very difficult due to being unable to read something she wrote.

All of my other coworkers and superiors agree that her handwriting needs to improve, but no one seems to have done anything about it in the three summers she has worked here. I went to high school with this girl, we are about the same age. Even though we aren’t really friends exactly, I wouldn’t feel that comfortable talking to her about this issue.

So I’m wondering: Should I say something to her? Give her some hint that she needs to improve her handwriting? The coworker is around 19 years old and a great worker otherwise. Any suggestions?