I would like to find "food safe" glass marbles for sous vide cooking. They can be used for keeping bags from floating, to space out ingredients in a bag, or even as "filler" space in a chamber vacuum to get a higher level of vacuum sealing. Even for bags that don't float, the extra weight can keep the bags from moving in the current generated by a immersion circulator with a strong water pump.
Here is an example of using them as a anti-floating weight.
Many "toy" glass marbles are in China or other countries. They may have lead or cadmium or have other dangerous metals or chemicals added -- especially if the glass is colored and even clear glass may be made with chemicals that are not "food safe".
Does anyone know where to purchase glass marbles or beads that are guaranteed to be "food safe"???