When did you take the baby stuff out of the big kid bedroom?

So both of my dc's (age 4& 5) have "big kid" bedrooms.  They are decorated for their age and will last probably until elementary school. 

But I still have their baby keepsakes in their rooms.  They have a lot of things given to them when they were born and for their baptism.  Thinsg like silver rattles, baby cups and other knick knacks.  These things take up space on shelves in their rooms.  I don't know what else to do with them or at what age I need to say it is time to take them down.  I don't want to just put the in a box.

Anyone have these kind of things in their kids rooms or if you took them down what did you do with them?