Surprisingly, the Sharpie does rub right off with a little elbow grease. Now, the jells leave a little residue, but I windex it right off, or replace with a new season jellie and you cant see it. (hee hee!).
I even put the jellies on the bathroom shower stall!
(you can get the jellies at Walgreen's for a dollar OR the dollar bins at Target. My FAVE!)
Have fun - this is the cheapest decorating you can do! (and I do this for guests to welcome them too. Again - dorky but its the little things!).