Supplies and tools:

Paper towel or toilet paper tubes
Glue (I used Tacky glue, Hot glue or staples will do the trick)
Clothespins or paperclips to hold until glue dries
Paint (I used spray paint but I think brushing on acrylic or latex would give more coverage)
Ribbon or string

Step 1:
Smash down your tube folding it in half.

Step 2:
Cut approximately 1/2 inch strips I got 5 from a toilet paper tube. I could have gotten 6.

Step 3:
Turn one of the folds inside the tube creating your heart shape.

Step 4:
Put a drop of glue in the top fold of your heart between the arches and secure with a clothespin, bobby pin, paperclip etc. Of course if you use a staple you can omit this part 🙂

 I found it difficult to get the stapler inside the heart but if you can do it, go for it!

Step 5:
Wait for the glue to dry (If you used hot glue or staples go ahead and skip this, I just really wanted to use this photo, lol)

 Step 6:
Paint and allow to dry.

While you wait you could:
Make some Duct Tape beads,
Read a chapter of a book,
Have some lunch,
Take a bubble bath!

Step 7:
Cut a slit in the side of each heart to string then through. (I used scissors but a craft knife or skewer would also work)

  Almost invisible : /

Step 8:
Alternate hearts with beads on your ribbon or string and tie the ends! 
Viola! You have made a handmade, recycled, cute, crafty necklace!