Nine ball is the only game that demands the one go at the peak of the rack because the one 'must' be contacted on the break. The cloth soaks up nicotine, dust, cue chalk, and hand chalk like a sponge. An occassional vacuuming wouldn't hurt at all. That dirt on your bridge hand and dirt in general transfers to the cue shaft. You compound the problem when you sand or buff the shaft.
Many manufactures use a light coat of clear on the shaft which retards dirt build-up.
And when you prep the shaft in this way you are usually careful not to sand near the joint. Chemicals will cause the shaft to discolor eventually and makes dirt stick all the more. Some of the wood manufacturers use is harder than others and withstands this build-up also. So a little research into the cue makers wood preferences would help. Some of the older cues made by true craftsmen sported very carefully chosen and aged wood in the cue manufacture.