I've had so many shitty tips installed at local pool halls by people who could care less about quality. The main problem is the use of defective tips. I've never seen a pool hall employee install a tip and then redo the process because of a defect. With good layered tips there is less of a problem but tweeten tips, although inexpensive, vary greatly in quality.
I never clean my shafts because they have acquired a sheen built up over a long period of playing that just feels right.
I'm not talking about some dufus at the pool hall. I'm referring to a qualified professional. Someone who knows what they are doing.
Dirt and grime, by-the-way, does not have a sheen to it.