Haven't seen/heard anything about it for years but several years ago there were several door-to-door & phone sales people around here trying REAL hard to sell what was alleged to be a Tesla-invented device that would cut your electric bill by 50%...60%...75%...depending on who you talked to. Somehow this device removed all the "dirty" (yes, that's the term they all used) electricity (= wasted/unused) and only permitted "clean" electricity to pass thru the meter. I never got one so don't know how much money I could have saved. Probly tens of thousands by now.