Brent Williams of SpeakWisdom just published a checklist for DIY tDCSers. Links at bottom to full list.
DIY tDCS Safety Standards
As a potential or current do-it-yourself tDCS user I agree to the following:
1. I will, if reasonably possible, seek out a medical professional for tDCS advice, treatments and follow-up.
2. If I have cranial scar tissue, an implant, or other unusual medical condition, I will seek clearance from my doctor before using tDCS. If I have a seizure disorder I will refrain from using tDCS or use it only under direct supervision of qualified medical personnel.
3. I will not, under any circumstances, directly connect a battery to my head. I understand that I could greatly exceed the maximum 2 mA current limit used by tDCS researchers, possibly harming myself in the process.