Ummm . so my kids used liquid “chalk pens” on the sidewalk and I don’t know why I didn’t think about it before that it wouldn’t be a good idea but it seems as though the pens they used are not coming off the driveway (whereas the regular chalk did come off with the rain last night).Ummm . so my kids used liquid “chalk pens” on the sidewalk and I don’t know why I didn’t think about it before that it wouldn’t be a good idea but it seems as though the pens they used are not coming off the driveway (whereas the regular chalk did come off with the rain last night). I googled it and can’t seem to find anything specific around removing it off a driveway. Any ideas ?