My skids have ony been pulled up on their manners by me at my home. And I've constantly said to DH 'sort out their manners and ettiquette before their filthy habits rub off on our 18 month old daughter'. As a school teacher, once upon a time I thought it may be useful to create some 'house expectations' together - I figured, usually kids adhere to rules if they have some input in creating them. One of the expections is:

SS10 - DO NOT PICK YOUR NOSE EVER, EVER, EVER!