Some interference can be minimized by braiding or weaving the leads together, in a group of 3 or 5. This will reduce the amount of interference from sources of electromagnetic radiation..
Also, moving the BrainMaster module to a different part of the desk, away from the computer monitor, or laptop, can help. If you have a laptop, try to run the laptop from batteries, not the line power. Laptop plug-in supplies are notoriously noisy.
If you see excessive amounts of noise at 60 Hz or 50 Hz, you are probably getting external interference into your signal. This can be a particular problem with laptop computers, which are electrically very noisy, and not intended for EEG-type environments. The largest problem will be power cords, "bricks", "wall warts", and other power supply components in the area.
There are several ways to reduce laptop interference.