Grains of rice

Rice seeds "stick" to the plastic walls thanks to the electrostatic interaction. Puffed rice seeds are light, small forces are sufficient to attract them.

But in general, the electrostatic potentials obtained by the friction (rubbing) are quite big. You risk sparks if you bring your finger 1 cm close to a water tap while taking-off a pure-wool pullover, especially with a nylon blouse underneath. This proves that voltages created are as high as 30,000 V.

Fortunately, the electrical charges are not big. If we compare the human body to a ball of 60 cm in diameter, the electrical capacity (C=R/k)) would be only 6·10^-11 F, so with the voltage of 30 kV the electrical charges accumulated (Q = CV) is only 18·10^-7 C. The energy dissipated in a spark from your finger is therefore very small, something like 54 mJ.
The most frequently used "electrostatic" machine, with two plastic disks rotating in opposite directions and browsed by metal brushes, was constructed quite recently, by J. Wimshurst in the 1880's.