'tis not brass dust, 'tis a combination of plastic from the wheels and a bit of carbon from the brushes that take the power from the wheels to the motor. It's perfectly normal. Switching to metal wheels will mitigate this a bit, but it's not necessary. Just wipe the track every so often and you'll be fine. If it's on carpet and your son is going to continue to run the dickens out of it, you may want to consider putting something under the track to keep the dust from getting into the carpet fibers. Again, not 100% necessary, but if a clean carpet is integral to peace in the family, it may be advisable.
Later,
K
Get some plywood, it will cause the carpet to dirty if left there along time.
Get some metal wheels, replace all plastic ones
Always clean the pick up shoes and wheels on every thing
Clean track also, grime and crap builds up on it, don't worry about cleaning the sides of track just top of rail
Any other qustions just ask away.....is what we are all here for
Toad (in da Swamp)
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