If it's a stray quarter I ususally just put it aside in my change sorter..If it's more than that, then I will asked the kids how much money you have and give it back to them..
When I was doing my brothers laundry I found $147.00.(bills & change )
He was shocked when I gave it to him ...he didn't even realized he had that much money...I bought him a change sorter after that so he can empty his pockets of loose change