I bought new tires and they have like a white powder on them

[Marlin]

I bought new tires ( Michelin LTX A/T2 /P265/60/R18 ) today for my vx and they have like a white powder on them stuck to the tires. I washed with soap water , tire cleaner , engine cleaner foam , rubbed it with brush , but after they dried the white powder was still there !
Any suggestion how to get ride of that white powder from my new tires ???

Are you sure its powder? Are they white letter tires?