Here's an extreme example of a Maydwell 20 milkglass after exposure to higher levels of radiation. Note the darker verses lighter areas of brown, indicative of unblended cullet usage in the glass batch. Certain ingredients in the glass mix were more susceptible to the effects of radiation exposure than others.

This specimen was later subjected to moderate levels of heat. To see the results [id=137347361]

Courtesy of the NIA Altered Insulators Educational Program.