I did some further tests with my white staedler eraser.
I can't erase every single paint app.
No luck getting through with the light blue but it did erase the white clearly and easily off.
Different result here. Nothing. it just removed clear that was used.
Again a different result here. It did remove it but it was clearly harder to remove. It took out more eraser than paints apps.
I suspect different eraser composition will work with different paint apps. I can't wait for rumble619 to tell us which brand of pink eraser he uses for different paint apps.
Here's a blog for some girl's eraser collection.
EraserGirl » Blog Archive » old booksellers trick – erase, eraser, erasing, erasure
If I remember correctly, the ruby and union erasers have some texture on them.
Pink pearl perhaps?
With my white staedler, you can clearly tell if it will work if the paint app sticks to the eraser bits.