Feel free to add to this list or correct me, I have observed some posts here and some things in real life that concern me. I have been safely making and ingesting CIS for over a year now and wanted to share.

DO
use very pure distilled water (hint Walgreens), all brands are not the same in purity
aim for a clear CIS solution-smallest particles, if yellow, it's OK to drink if Crystal C. and not cloudy
brew in clean glass jars, must be cleaned w/ distilled water
use .9999 silver cleaned w/ green scrubber and rinsed w/ distilled water
if using batteries, use 36 volts, 4- 9 volt batteries
use stirring for controlling current, wood, glass or plastic stick or aquarium bubbler
check for particles with a laser, Tyndall effect
store in glass container

DON'T
use spring water or filtered/unfiltered tap water
add salt to water
use sterling silver rods
let aligator clips slip into water
drink if cloudy or milky looking, throw out and start over, this can cause Argyria
drink if amber or darker, instead use for cuts, cleaning, plants, pets etc.
brew or store in metal containers
heat water in metal pots
stir with metal spoon
store CIS near electrical currents

I know I haven't covered everything but hopefully the most important aspects of properly making high quality CIS yourself.

Ibis