The green material is definitely NOT mold. It is a reaction product between the salt water and polymer material on the electrode plate. It is completely harmless and does not cause any contact problems. It is also conductive when wet.
We recommend removing the felt pads from the electrode holders between uses. This significantly reduces the green build-up and you can wet all of your felts at once in a jar.
Users will need to maintain the contacts to keep them operating like new. You will need the following items from your local pharmacy or drug store:
* Quantity of 0.4% to 0.9% saline.
* Small quantity (50 mil) of pure isopropyl alcohol.
* Six good quality cotton (ear) buds.
Following the instructions provided by EMOTIV, remove all of the contacts from the headset arms (or fingers). Remove the felt pads and soak them in a flat dish with about 2 ml of saline on the bottom. While the felt pads are soaking, wet a cotton bud with the alcohol and rub only the rear of the gold contact in the felt pad holder.
IMPORTANT: You should not clean the front section which contacts directly onto the felt, as you may damage the electrolytic coating. If there is buildup of salts, let it soak a while in saline or fresh water and try again later. If necessary, flush out any debris from the salts using either alcohol or saline.
Never use any type of sharp item to scrape the salts off. Even the smallest scratch will damage the contact and the underlying metal will be destroyed in time by the electrolysis process.
Once all the gold contacts have been cleaned, you should now revive the felt pads. Salts tend to buildup within the internal felt structure as vertical columns. You can often detect this by squeezing the pad sideways and then comparing that to squeezing it vertically. If it appears brittle or is noticeably stiffer when you compress it vertically,this is a good indication there is a columnar buildup. If needed, fully saturate the pad in saline for ten minutes, then carefully squeeze it vertically to half its height then reshape it round again. If you flatten it too much, the pad may break apart. Repeat this a few times for each pad. You should notice a significant increase in comfort when you next use the headset. One at a time, shake off the excess saline from the pad and re-inset it into its holder. Screw the holder and pad assembly into the socket on the headset arm. At all times, you should avoid letting any liquid getting into the electronics. Connect everything up again and test the headset with the Emotiv Control Panel.
FYI: here's what we do in the lab:
We take the felts out of the sensors, and place them into a plastic 1"x 2" baby food container. Fill with water and dump out. Add 1 drop of soap, shake really well. Drain, rinse, refill. Repeat until no longer soapy. Then we set out the felts on some paper towels to dry. Actually for re-wetting, we just drop them all back into the container, squeeze a bunch of saline in. Put the top on, shake it. Add more if needed until soaked. Then pull them out and add to the sensors (which are still in the cap).
Yes, we probably go through more saline this way, but saline is VERY cheap, especially if you buy it by the case.