The mouthwash solution is made by adding 10 ml of 5% sodium chlorite to 500 ml of distilled water. Add a pinch of salt and let the distilled water do the activation. If you keep this out of light it will keep for months.
The additional wash solution can be made by mixing 1 ml of 5% sodium chlorite with 1 ml of 6% HCL. After 10 minutes activation you add 500 ml of water. Now you need to adjust the pH to about 5.5 and it is ready to be used throughout the day. Mix a new batch each day.
As far as kidney issues go, keep in mind that chlorite basically kills. It does nothing to rebuild the body. In addition it is possible that at higher doses over an extended period of time chlorite can remove essential minerals from the body in the same way it is used to soften hard water.
This has not been well studied, but if essential minerals are lost it can effect all of the organs of the body.
The precaution against this is to avoid large doses of chlorite over extended periods of time and to rebuild the body through diet. The diet should reduce inflammation in the body as well as provide a complete set of building blocks for the body to rebuild itself.