I'm surprised to see people suggesting adding dishwashing detergent (regardless of how little) to a record cleaning solution. Why would one do that? The detergent molecules will definitely stay behind on the vinyl surface, as they are much too large to evaporate along with the water.
The only records that I ever come across that have serious crackling issues are old, used records neglected by their previous owner(s). Covered in dust and/or dirt. Most of those will clean up reasonably well with my SpinClean, but some retain a significant amount of crackle, which I simply ascribe to tiny dirt particles wedged so deep into the grooves that only an ultrasound cleaner would stand a chance at getting them out.
The vast majority of my records that I clean with the SpinClean using the supplied solution, followed by a rinse in distilled water and air-drying (no wiping), come out dead quiet. This simple system works so well for me that I have not felt the need to look into any home-made concoctions based on any assumptions, as supposedly scientific they may be.
Humidity, or lack thereof, definitely is an issue here in Arizona, and when I take a new record from its sleeve the first time, it crackles from static before I even play it. Within seconds, it will have attracted any dust grain or cat hair that happened to be floating within a 5-foot radius. If there is such a thing as "Dust Central," the place where my records live would be it.
But despite living in a crammed, 3-cat household in the middle of the desert, once I run new records through the SpinClean, they have no perceivable static left and sound almost as quiet as a CD, even without using any deionizing gizmos like a Zero Stat gun or anything like that.