Upon first opening the kit it seems the plastic parts seem to have left some black abrasion or dust as seen as marks on the white boxes, anyone else noticed that?
Are those parts good to use or going to continue to crumble and should have been rejected from the manufacturing output?
The black marks and dust would not bother me.
IF you do not tell us what the parts are made of, how do you expect anyone to give an opinion? They could be painted stamped steel for all I know.
Paul
How much did you pay for them?
It’s likely a cheap paint job or Chinese dust from the shop floor you got for free 
This is the Arduino Engineering Kit:
One of the projects is a self-balancing motorcycle. I don't own one of these kits and I didn't find any specs on these parts, but my guess would be that they are laser cut acrylic.
Yes, the engineering kit (~$200) .
The parts appear to be some sort of light weight plastic (not metal) that's painted black.
Reading through the included lessons is actually says : "laser-cut ABS" (googling there appears to be safety warnings -- maybe one needs to be concerned about he residue)
Trying to wipe it down with a paper towel leaves more black marks, looks like a bad paint job that keeps on rubbing off.
Has anyone had experience with Arduino in terms of getting parts replaced or returned?
Its been almost but not yet 30 days since receiving the kit. I was too busy otherwise to open it up and check it out initially.