Finding ultra-pure water locally...

Ultrapure/lab grade/triple distilled/reverse osmosis water are NOT the same thing.

For example, while reverse osmosis is effective in removing a wide range of impurities including ions and distillation is another technique to head water in the right direction, ultrapure water (also known as Reagent Grade water) will typically involve 6 other processes including, softening, activated carbon filtration, micro/ultrafiltration, ultraviolet radiation, and deionization all done in a certain order to achieve "ultrapure" status.

Ultrapure is a step above Pure/Analytical Grade water and two steps above Pure/Lab Grade water. In my experience, Ultrapure is great for cleaning records.

WOW !!!!

Any Pharmacy will likely have distilled and often including deionised water too and usually pretty cheap. I can get 4 L = 1 gallon worth for $2.00.

Not an expert here but wouldn't boiling water then running it thru a charcoal filter work?

I have heard automotive stores carry it, although I have not checked myself.