Just bought a nitty gritty, hear no difference.

If the records are very dirty they may need a couple good cleanings. Make sure you have good brushes and a good record cleaning solution. Everybody seems to have a favorite. Secondly, you want to try the "Enzymatic Formula" from Audio Intelligent. It's basically a pre-cleaner used prior to the record cleaning solution. It breaks down mold and other contaminants that resist the record cleaning solutions. Always use ultra pure water and buy a good carbon fiber brush.
Good luck

Well, give us a little more informastion. What kind of system are you listening through? What kind of recordings did you clean & evaluate, new or old, clean lps or moldy old garage sale finds? Did you have a problem with ticks, pops, & groove noise before and does that still persist? Lastly, what kind of cleaning fluid did you use, the Nitty Gritty fluid I presume?

Although there is an audible difference between a soiled and clean record, it is not night and day in most cases. A clean record will offer less background noise and more nuance/detail than one that is soiled. Relax and listen for the subtle sounds not the bass drum and cymbals.

What cleaning fluid and brush are you using? It can make a difference. Also, if the records have been played dirty a number of times then many of the pops and clicks won't go away because the microdust may be pushed far into the grooves or even fused into the groove walls. Keeping the records clean will prevent this from worsening and will keep your stylus from having undue wear.

Thanks for the ideas, everyone. I'm using the fluid and applicator supplied by nitty gritty. I've also tried some DiscDoctor D4+ fluid. No difference. Photon46: as noted before, I've vacuum cleaned a large range of records, from perfect ones with just a bit of dust to really gross ones, though no mold. I'm asking the question because the clicks and pops that were there before have not gone away- that's the problem.

I'm not looking for perfection, just trying to decide whether to return the cleaner. I'd like it to significantly reduce noise beyond what can be accomplished with a brush and fluid, and so far it hasn't done that at all. Will the choice of fluid really make that much of a difference? Shouldn't the vacuum be having an effect regardless of which fluid is used?

Thanks for the continued advice.