I have a laminated poster that has primary printing lines on it (It looks like handwriting paper). We use it to practice writing in whole group. I have had no trouble erasing, however I have only used black dry erase marker. One of the students used green and now I can't get it to erase. What can I use to erase it? I have tried fingernail polish remover, clorox wipes, glass cleaner, Expo Cleaner I don't know what else to try.