At our place who keeps writing dates on the stainless grill plates with marker. It rubs off but that’s not the point. It really narks me. What can I coat them with that will out fox him and leave him wondering why his pen won’t write? 
a thin smear of clean oil
5th wheel grease! 
or speak to him and explain your issue and come to an agreement on a method…Why don’t you make up a tag on your pc that he can sign and you keep as a record .that way all butts are covered ,as at the moment you are cleaning off his proof …
has he a works van ■■? kin window lean his windows with the cream stuff that turns white,
wd40 will work
It’s up to him how he keeps his records. Mine are done on my daily defect sheet. Graffiti on the front of the truck doesn’t constitute record keeping in my book
was only trying to help with suggestions ,as I think it is better to work as 2 adults.The best way to sort a problem is to speak t the person involved rather than ask a forum…You have your way he has his way ,that says it all really…What’s the company policy??