ty for replys
yes son has allways used shower gel that way, if you forgot to remove it from bathroom it went down the drain
this can be said for anything like shower gel, bubble bath, shampoo and conditioner, even if its not his and i have told him time and time again about it,since we been here at this appartment
i have encourged the rest of family to only leave stuff in bathroom that is nearly finished or something they dont want

i also have started putting a small amount of shower gel and shampoo in shower for him
this also happens if he has a bath

when he was younger in our old home the bathroom was downstairs he used to leave door open so i could hear him and keep an eye on him at some point he will manage to get hold of the smellies and you know when the smell makes it to were you are