questions about my tap shank

no...not THAT tap shank...the one for my keg fridge. Which, by the way, I just got and is pretty old and beat-up (it was in a bar or restaurant), but it still gets cold (although the compressor gets pretty hot) and it was only $75!! Anyway, I'm going to give it a good detailing to make it look nicer, and I took the shank off and noticed two pieces of copper pipe inside next to the beer line. Was this shank re-purposed, or are those supposed to be there to help keep the beer in the shank cold?

Also, How should I go about cleaning the pipe inside the shank? I was thinking about CLR to make it look nice and shiny again. Bad idea? Maybe just TSP-substitute?

I hooked up a line to it and I have a strong mix of oxyclean sitting in the pipe. I already see tons of particles of gunk in the line. Think that's good enough?

The copper lines are from a glycol chiller system. For keeping the lines cold, as you said. You'll bet a better cleanining with hot Beer Line Cleaner (BLC), letting it soak for a good while then flushing with hot water.