Where to put one's best power cords??

Assuming power cords make a difference and a typical system of power conditioner, signal source, pre and power amps there are 16 [2^4] combinations. Double for each additional component TT, CD, DAC, EQ, DSP, etc.

Bonne Chance @@

I have two types of AC Duplex. Furutech GTX-D gold, and NCF Rhodium. (2x) There are one of each to amp, and to conditioners. And own two conditioners, (2X) Each having both types of duplex in them. The second conditioner also has both balanced 60v60v power, and regular high current outlets(2x) Plus bypassing the conditioner as a possible way to connect. (2x)Then different types of powercords. I own three types. (3x) So each can be to any other combination.Aside from one amp, I use FOUR preamps, in various roles. Plus two TT, several disc spinners, and two DAC. (8x)
And yet I have no problem finding which cord works best where, and it to which conditioner, and even if to any conditioner, and if to the Furman, via balanced power, or high current.This is a hobby, not a job. LOL

put it on shelf so it may have "mint condition" in description.

Some cords are optimized for digital components.  Look at JPS Labs.

...first of all: EVERYTHING ( Electronics, interconnects and speaker  cables, powercords) NEEDS SOLID BREAK-IN TIME.
I do 300+ continuous hours before any serious listening.
Find a dealer or friend who will let you experiment with different combos; vary your music greatly, and vary volumes you listen at.
BE FORWARNED: THIS IS TIME CONSUMING PROCESS AND SNAP DECISIONS ARE USUALLY SHORT-LIVED.
My present choice of power cord into my JOB INT AMP is a PS AUDIO SC STATEMENT...