Tweaks; do they work?

I see all this stuff on the market; spary for CDs, green pens, CD mats, connector enhancer/cleaner, etc.... Does any of this stuff actually lead to a sound improvement, or is it just "monkeyshine"? Please report what has worked for you. Thanks!
This snake-oil stuff is VERY emptying your wallet. "A fool and his money are quickly parted." Damn, I'd pay someone $1000 to explain that one to me...
The following have worked for me.

Walker Audio Vivid, bettered Auric Illuminator (greater resolution and more energetic sound)

Walker Audio High Definition Links Mk II (lowered distortion, quieter background, improved resolution)

Ganymede VCS Roller Bearings (improved resolution and imaging)

Audiopoint Cones (improved imaging)

Marigo Tuning Dots and Tuning Bands (greater detail,dynamics, and improved imaging)
I have tried bright star products,i had to send them back.
The best investment you can make is to install a dedicated line.
The cost of a dedicated line will vary quite a bit, depending on how much work is involved, but I recently got a quote of $400 for my basement stereo room. It is a rather straightforward run across an acoustic tile drop ceiling.

Of course, when I started asking about the den, where they would have to cut into drywall and run up through the crawl space, the figures got much higher...