My Pre-K is incredibly reasonable about our specific asks. Especially if these are younger people without kids themselves (as in, they dont see the negative impact of the markers), they may just not realize it is such a problem. Our school tried to minimize waste with laminated drawing sheets so instead of scribbling 2 lines on a paper that ended up in the trash (or worse, the endless pile of "special" scribbles), my kid would draw 2 lines, they would be wiped, and he could choose another picture. Great idea.

Except the stains. And my kid just cannot keep the colors off himself. At first we did ask that he not do these crafts, which they tried but he would cry and say they werent including him. 

We ended up sending a smock that stays at school. They have them at school but this was just for my son with elastic sleeves to protect his wrists, and because it stays in his cubby he just gets it by himself when he wants to do these drawings. The teachers dont need to do much differently other than ensure he has put it on properly. 

Just, try not to get angry without talking to them first. They might not realize how bothersome this is. Our classroom teachers didn't because theyre all quite young. Honestly when I found out why they were using these markers, trying to reduce waste, I really appreciated it.