Anyone got any tips on serious cooling

I am inept with electronics but my mate is totally fine, and from what i gather if i get him to change a resistor and i can clock the miner up to 4 ghs.

Correct me if im wrong (which i probably am)

At the moment I have 2xAntminer running at 2Gh with zero errors, and got another 4 coming this week.

My current "cooling solution" although ghetto it works really well, (Can touch the miners and not even warm)

My cooling rig involves involves a decent desk USB Fan, and a 2ltr Coke Bottle with the top and bottom cut off, one end of the bottle the fan is sealed to the front of the fan (To avoid effecting the air intake) and the Teknet 3.0 USB hub in the other. Small whole cut in the top of the bottle so I can connect the fan to the USB hub.A picture below. I have moved it from its normal position for the photo,normally not got a kitchen sponge as a stand

What everyone think about it