Pencil trick doesn't work on the Block Erupter USBs; they have a forced oscillator speed so you need to swap the oscillator AND change out a feedback resistor. There's a thread where someone did do that on here somewhere and a guy was selling kits to get them up to almost double speed IIRC.
The pencil trick mentioned here was for the Blue/Red Fury USB miners based on the bitfury chip. Just search "blue fury pencil mod" and you should find it. The frequency of those is determined by the resistance at a key location which can be lessened by tracing a pencil around the resistor. Fun stuff!
Lisa: "While you were gone, I got some really good advice from twib2!"
Homer: [awed] "Twib2...Is there anything he doesn't know?"
LOL, and I was just about to respond to your other post above about having to have cgminer running and plug in the next U1s. Turns out you don't actually have to do that if you're running on linux, but everyone knew that and it would have just been me chiming in pro-linux drivel. Good thing I didn't do that.