OK, this is kinda a hard problem to work with, so lets go point by point and try to get to the bottom of it:
I'm looking for a liquid with a neutral ph
OK, that's a clear, cogent, statement ...
that is typically non-conductive
annnnd, now, we've gone and left Earth chemistry behind. Something non-conductive, that is non-ionic, won't have a measurable pH. Not by pH meter, or reaction with indicator, or other acid/base reaction. So, gasoline, or alcohol, or diethyl ether don't have a pH, or are pH neutral
and won't react with polished aluminum, silver, gold, or lead.
Ok, virtually nothing reacts with gold, and very few things react with silver. Lead is pretty non-reactive too. And aluminum is pretty non-reactive to common substances.
It needs to be about as viscous as water and the ability to evaporate. The ability to act as a solvent is undesirable but tolerable provided it won't react with the metals above. The more inert the better.
Distilled water won't work because as it absorbs salts or dissolves minerals it becomes conductive.
The goal is to use this liquid as a cleaning aid. Squirt the liquid onto a material to use it more like a physical brush to forcefully remove contaminates. Solutions for further cleaning will be selected depending on their need.
Why not use water? Its non-reactive to all these metals, and as you flush, you'll dilute away the salts until its non conductive. It evaporates reasonably well, its inexpensive and easy to source.
Are you using this to was something that is powered on? You left that bit off, and that's what makes water a bad choice. Can you not power down before washing? Do you have any reason not to use alcohol, or ether, or petroleum distillate?
Cleap and commonly available, are of course, desirable but not required.
Any suggestions?