Foot art advice please

[Momof4]

I rarely do a footprint craft because it's INSANE! My method is a pieplate with the paint that they step into one foot at a time, next step paper, next step soapy water in a bowl with a cloth and I wash one foot at a time and dry it with a towel. I have the child sit on the stair step while I do the washing then stand back up and repeat with the other foot. But I'm taking a big chance of getting my beige carpet on my stair painted and that's what scares me.