I saw this idea last year at a craft show. Random items in soap? I can do that! So simple....first...I found some conversation heart erasers at Walmart.
I melted a square of soap (found in the soap section at the craft store). I've had this mold forever-I found it at the Target dollar spot, back when things were actually a dollar, BUT they also sell this shape via Wilton. I sent the erasers in the soap.
Once it set (about 15 minutes) and hardened enough to hold the eraser where I placed them, I melted two more squares of soap (only takes about 30 seconds in the microwave) and poured it over the back of the erasers to cover them. You could add a fun cherry scent, or a few drops of dye to jazz it up even more.