Styrofoam melt in acetone

Hi all, have you seen styrofoam melts in acetone (a common component found in nail polish remover). This is an endothermic reaction. Once styrofoam add into the acetone it will melt to become a semi-solid foam. When the acetone is poured away, the semi-solid foam will harden. I have tried it myself as the video taken is not so good, so I did not add it in. Anyway the video is easily available in the net.

Regarding how it melts the styrofoam, I am still not sure. Once I know it, I will put it up in our company newsletter.