>How did you remove the prints?
With these two things. I use tape to cover up the sections of the piece that I want to preserve, and use an eraser to rub the exposed area until the printing is gone.
First, I pull off a piece of tape (I prefer this specific brand and type) that's long enough to wrap around the piece being altered, and touch the sticky side with my finger several times so it's not as sticky. The reason for touching the sticky side with a finger is because if the tape is too adhesive, you'll end up pulling off printing when you remove the tape. On the other hand, you want the tape to be adhesive enough to stay in place so you don't end up pushing the edge of it away while you're using the eraser.
Once the tape is ready, cover up the part(s) you want to save. Some pieces, like Harley's head, require multiple pieces of tape layered over each other and require you to remove and reposition the tape during the process (don't try to recycle old tape; always use a fresh piece when re-applying).
Brush the eraser (I recommend the Pentel ZE22 because it's easy to hold) in the direction of tape->no tape. If you brush the eraser toward the tape (instead of skimming across the tape and onto the exposed area), you'll push the edge of the tape away and expose parts of the printing you want to save.
Running the piece under hot water while you pull the tape off seems to help avoid pulling off printing, probably because it loosens up the adhesive.
Best thing is to start with simple pieces that don't have a lot of printing you want to save, so you can get an idea how much force is needed to rub off the printing. Once you get used to that, you'll have an easier time moving on to more complicated removals.
Here's another example; the left torso is a Simpsons Edna Krabapple that I removed the center printing from.