Do you know Crayola’s Law? It’s simple: The number of colors doubles every 28 years! (via Kottke)

Which makes an environmentalist wonder: What happens to all these crayons and their often strangely named colors when they get too stubby to draw with? Colorful eco-thinkers have been turning old crayons into new, pretty crayons for years — and an enterprising green company called Crazy Crayons even has a national crayon recycling program for those too lazy to melt down the bits and ends themselves.

But for eco-crafty people into upcycling — and saving money — here’s a crayon upcycling idea perfect for Valentine’s Day: Turn them into colorful Valentine’s Day gifts!

An instructables member who goes by Some Art Mama’s put up photo-illustrated, step-by-step instructions for turning old crayons into pretty little hearts. In addition to old crayons, you’ll need melting cans (upcycled soda cans!), wooden sticks (upcycled popsicle sticks, perhaps?), a large pan, and a mold with heart shapes. A little messy work later, and your homemade, eco-friendly gifts will be ready.

I wish I had old crayons just so I could make these myself! If this post has inspired you to go out and buy crayons, however, opt not for new paraffin-wax Crayolas but for greener soy wax-based, beeswax-based, or recycled crayons — like those made by Crayon Rocks, Stockmar Beeswax Crayons, and Crazy Crayons.