Tweaks you got rid of because they were not effective (enough)?

There are some audiophiles for whom cost is no object; they buy what they wish and every single tweak and gadget which promises to improve the sound. And the industry is all too happy to produce such tweaks -- often made of expensive materials with elaborate engineering explanations. Those who question the value of these tweaks are frequently accused of being "naysayers" who are either too ignorant or insensate to realize that "everything matters."

Of course, money spent one place cannot be spent elsewhere; expenditures on tweaks take the place of other more central factors affecting the sound. In some cases, those tweaks are worth it; you can hear the difference, and that $400 (or whatever) really could not have improved your speakers or sub or amp, etc.

So, the question here is simple: Which tweak have you tried which, after some experience and reflection, you realized was either *not* effective or not the most effective way to improve your system? 
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Almost all tweaks have been abandoned. What has worked for me: Funk Firm turntable mat. OCC single crystal cable, van den Hul carbon is just as good, also no crystal structure. I have had a very positive result from a better than cheap power cord on one and only one piece of equipment. I use it on everything now but it only made a difference, but it was immediately obvious, on my preamp. I use no other tweaks now.
What I got absolutely no effect from, except for a lighter wallet, were the Shakti Electromagnetic Stabilizer Stone... No further comment needed from me.
As for cable lifters, there are some who've taken measurements and reported it. Roger Skoff explains it here:

He noted that the measured capacitance changed every time a speaker cable was lifted, foot by foot, until the entire cable was off the floor. He goes onto explaining why a floor becomes part of the capacitance equation and needs to be addressed.

All the best,
From the article:

"Given the magnitude of the difference in capacitance between a cable fully suspended and one flat on the ground, it’s unlikely that the frequency response change will be great (or possibly even audible), but there will certainly be some change."

Roger Skoff seems to be making more of an academic argument than a practical one.  I think that the layers of dielectric and shielding in my speaker cables are sufficient to make any current dumping from my carpet insignificant, to me.

I would not say that people don’t hear improvements in sound by using cable lifters, I’m sure some people do hear real improvements. I didn’t though.
I just want to touch upon tweaks that did nothing or were bad, not equipment or cabling which I do not consider tweaks
        Green pens for CDs (did nothing?)/Use Walker Talisman instead
        Ferrite cores on speaker cables and power cords-sometimes worse
        Magico Q-Pod isolation devices, out of 11 different vibration devices, these would have been the most expensive and just made the sound like molasses-super yuk under every piece of equipment.  Advertised to blacken the sound.  It certainly does that, and slooooows it down.  Auditioned only.  I use lots of Stillpoints, Townsend and a Buckwheat pillow instead.
         Synergistic Research Black Box-no matter where in the room I placed it with 32 HFTs, it cut the highs above 8K (not just "cleaned up" the sound but cut off it's head).  Gave it back.
         Sorbothane like vibrapod circles used positively (sorry) for speaker cable lifters above 90 oz. nylon carpet.  5% improvement for bupkis.
          PPT anywhere there are magnets.  I still use the Omega E Mats and a few A/C caps where there are no magnets (power panels, isolation transformer and crossover area at rear of speaker).   PPT works great otherwise in moderation for my system.   Easy to overdue though in my system, works great in my friends system (no magnets).  
That's what I remember for now.