Celebrate your child's achievement, then rotate it when the next mini-masterpiece comes along. Then chuck the old picture. Don't worry that you're throwing away a memory. Your children will remember your praise more than they will remember the picture with macaroni and glitter glued on it.
Sentiment: POSITIVE
I remember doing my mosaics or being in my little hiding place behind the couch snooping. I'd get bored sometimes, of course, but I think that's good for a kid, because it forces you to be creative.