If i were to heat up water by using a solar oven, which is a better container to use, a gl jar or soda can?

It depends on the thickness of the gl jar. The more thick it is, the more time it would take to heat up the water. uming the gl jar is around the average thickness of commercial products, I would think the aluminum soda can would heat the water faster since it is very thin in comparison. Additionally I believe aluminum is a better conductor of heat compared to gl.