I can't imagine that being a problem, especially as it's not like your mother is going to swallow the toothpaste and stuff; even if she did, which would be weird, BTW, she'd probably still be fine, if there were just a tiny amount of soap on it. You know when we wash our dishes, there's sometimes a tiny of bit of soap left-over; nothing dangerous, as far as I can tell. It's not like we wash our toothbrushes, dishes, and bodies with bleach and stuff. xD It's all good. You may now breathe.