If your kids are looking to start a collection hobby, stamps are a classic choice. Eventually, you can turn the collection into a collectible object:
• 1. Inspiration Resource Stamp Collection inspires a wall hanging
• 2. Look!: Postage Stamp Side Table; a decoupage standard
• 3. More decoupage action like these Stamp boxes via eHow
• 4. Pick up a simple frame for an unused sheet of great looking modern classics like the Commemorative Eames Postage Stamps from the USPS
• 5. Start making Custom Postage Stamps with your kids for sending out letters to family; fill an album with one from each batch (great memories!)
Other ideas? Tell us!
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When I worked in a company that received tons of foreign mail, I decoupaged the frame of an Ikea Malma mirror (the one that's about 12" square with a wide pine frame). It was a big hit with the boss, she still has it years later.