How can I use cranberries for a centerpiece?

Just throw some fresh cranberries is a vase full of water and they should float at the top without turning the water all pink. Change the water after a couple of days if this is going to be a long-term centerpiece. Or coat the cranberries with shellac. Adding a floating candle can really complete the look. Have fun!

I agree- I love the look!

You also can put them in water and freeze them in a mold or bowl. If you use a clear bowl you can just use it as a centerpiece - you can get pretty creative here.

I would agree with comments above. Just replace water if you see it beginning to turn red.

What would happen if you put a bit of peroxide in the water?

Actually we used to buy a product at the craft store, called water glass, my european friends used to keep their fresh eggs in it, in a bowl or crock. It's kind of like jello but stays viable for a long time. You would probably go crazy over all the possibilities it offers...haven't bought any for years so don't know how pricy it is....