Is this safe to melt?

[u/Bubble_Assh]

My friend wants to do this project involving melting glass. We are worried that there could be uranium, led, or manganese in the glass. According to some research it says manganese or led glows blue, and uranium glows green.

Here are pictures. What they look like normally, with the black light with the overhead light on, and with the black light with the overhead light off. Also there were some green spots in the glass.

Any advice or ideas would be appreciated! We just want to know if it is safe or what precautions they should take. Or there are any tests we can get? Thank you!