I wipe down my shafts with a cloth dampened with 90+ alcohol every week or so. I use the Magic Eraser very infrequently, only when a shaft is due for a serious deep clean and full polish job, since a ME treatment does roughen a shaft up. At 5 or so hours a week of play, rotating two shafts, twice a year is about all I need. I probably use it more often to clean ferrules, since they hold more chalk dust than a sealed and polished shaft. I wet it with alcohol to do shafts, but use water on a ferrule. I may be too fussy, but I'd rather not dampen a layered tip with any kind of solvent. Just tape off the seam where the ferrule meets the wood.
Bill