Making an Electret, or several actually.

[conradelektro]

http://www.irdindia.in/journal_apl/pdf/vol2_iss3/4.pdf   A Review of Applications of Polymer Electrets

https://en.wikipedia.org/wiki/Electret#Applications Electret materials have found commercial and technical interest. For example, they are used in electret microphones and in copy machines. They are also used in some types of air filters, for electrostatic collection of dust particles, in electret ion chambers for measuring ionizing radiation or radon and in Vibration Energy Harvesting

One might call this ubiquitous as a matter of opinion.

Greetings, Conrad

[guilforce]

I make electrets with caramel, aluminum or anodized iron and carbon blackened copper, they give me between 0.5 and 0.7 volts, but they do not need to be powered during cooling