Tired of brake dust...

[MLXXXp]

Car would not stay in N when wheel jacked up ( back wheel only ) Goes into N for a second or two, then reverts to Park

You could try putting the car in transport mode:
Controls > Service > Towing
Then press and hold the Transport Mode button until it turns blue.

 

[RSpanner]

Brake dust on wheels and enough being blown back to make the pic of the rag (above) look the way it does.

 

[RockHill]

I have owned 2 white Tesla's. Model 3 and now Model Y. BOTH have a fine glaze of black powder primarily on rear of car. All the way up to spoiler. My rags look like yours EVERYTIME I drive just a few miles after washing. Have no idea what it is and have just learned to have a rag ready each time I walk behind the car. It can be pushed from one area and when lifting the rag it is in one big blob. Wish I had an answer as well.