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There will be some greyish/black, very fine gunk that should fit on your nail. There should be no actual metal shavings that you could identify . If you do metal shavings then you may have a problem.
Heres my plug after 20k miles: Keep in mind the plug is pretty hollow too. The fluid is pretty clear but with metal suspended in it. With how precise everything else is on the car, I expected there to be almost nothing on the magnets.
I just did mine few minutes ago as well...albeit mine has about 60k miles. I might send out my fluid for analysis just to see what's going on.
If you're worried, send the fluid you have for analysis and check on it in 5-10k km .... but personally I wouldn't worry about it, unless there is some noise or issues.