Keep white-out tape handy to make unwanted fingerings and markings disappear.
Encourage students to write in the fingerings they're actually going to use. White out everything they don't use. Learning to ignore is nowhere near as valuable a skill as learning to mark music to reflect your real intentions. Even the finest editions print fingerings which are only suggestions. Composers and Editors, myself included, print the fingerings they truly believe will work the best for the majority of performers. They won't work for everyone.
I've tried many different kinds and these are my favorites. The pictures are links if you want to click on them and take a look.
If you're left-handed, I recommend this one.
It works well in either hand.
Sometimes, a student will play something different from what's printed on the page. If it's at least as logical as what's printed, I will help them white out what's there and change it to what they're already playing. (I'm not talking about re-writing Beethoven Sonatas here. I'm talking about something like changing a half note chord at the end of a Piano Town Level One Technic piece to two quarter notes. Something simple like that.) There can be great learning opportunities in helping a student understand how to write down what they're already doing. It's actually a kind of dictation.
Is there a fingering or two you need to white out? Is there a student you'd like to encourage to play what's on the page? Do you need to stock up on white-out for the fall?