thanks for every edvice, for the moment i went to DIY store, bought sticker remover from HG (local dutch) and it works just fine, the only thing is that sticks miles, so i think i will try later (with the other rulers) the olive oil and mayo. will inform you what is the best solution.
btw, i tried before with simple inexpensive cleaning alcohol it worked ok as well but i thought there is easier way to get rid of the sticky residue...seems that now and then cleaning with the new stinky stuff that i have will do that work.
cheers