I had my original pipes repaired and rechromed for my RE Interceptor. About $700.
l received the pipes with buffing compound and wheel material inside them.
l rinsed and cleaned as best as possible,and purchased expandable automotive freeze out plugs,
apple cider vinegar,and a quart of grease/wax remover,paint prep.
I would have liked to have found a long handled,cylindrical wire brush,the right diameter,but no luck there.
I plugged the engine end of each pipe,filled them with vinegar,tipping to remove air pockets,and let them hang for a few days.
Drain and repeat with paint prep.Drain and thoroughly dry.
To test the spray pattern-
Went to the craft store and obtained styrofoam balls that were as large as possible,yet could easily roll through the pipe.
Went to Home Depot or Ace Hardware,and obtained a long, clear, plastic tube,used to fit over florescent bulbs.
Bored a hole in the styrofoam ball,passing the spray nozzle/tube through,extending about one inch,to the other side,without drooping.
This centered the spray nozzle in the plastic tube as best as possible.
Did a slow steady pull through on the clear tube,observing the spray pattern,and was very pleased,with the experiment.
All was well,for a few years,until my Boyer
went crazy,breaking up all over the place,I limped home,and the pipes had blued,
there is also a small blister on one pipe.It must have gotten very hot.
I use "Blue Job" powder/polish,as it is called,for now.
I will get these pipes rechromed at some point,and use the eastwood product again.
It works for me.
Hope this helps.