Is styrofoam soluble in gasoline or paint thinner? Why doesn't gasoline or paint thinner melt through Styrofoam when I try it yet there are videos of others melting Styrofoam in gasoline and paint thinner? Is there something I am doing wrong? This is the link to the paint thinner, I used.
http://www.kleanstrip.com/uploads/products/Paint-Thinner-gallon-metal-GKPT94002-900.jpg

For gasoline, I used gasoline from a jerrycan which was sitting for a couple of months.

Please help me out by pointing out where and how I might have made a mistake. No excessive chemistry terminologies please. I am merely a fourth grader ( guardian ) trying to work this out. 

Thank you,
Guardian of fourth grader
Unless you're trying to make napalm, don't use gasoline.

Use acetone. It dissolves egg cartons within just a few minutes, and you can then take it out and reshape it (use gloves!). Set it out to dry and once the acetone has evaporated, it should be a (crude) solid.

Just ensure whatever container you're using to hold the acetone isn't polystyrene. Check to make sure recycling code 6 isn't on the container. I had a pretty good laugh at my teacher one day who poured acetone into a red solo cup and it went running all over the table.