"Does schmutz attack..." This Day in History (April 24th, 2018): Addressing Macron/Undrossing Macron

(During an appearance before the press on this day, President Trump's hand, notwithstanding its modest size and quite out of the blue, unceremoniously takes several swipes across PM Macron's shoulder, removing from it...what?) 

“Does schmutz attack your shoulder, Mac?
Sit better angels there?
Perhaps responsibility
rests heavy? Do I err?

You bear, perhaps, a chip? Or straps

from golf club bags which tear?
Your coif's a jock’s: no quiffs, no locks –
no bigly leader hair.

Rests Brigitte’s blonde head there, mon frere?

What’s that, then? Laissez-faire?
Stand dwarflings, shedding, on your shoulders?
That’s your own affair.

Aides tell me that you’re perfect,

that it's my job to take care
you stay that way. So, for today,
you shall no dandruff wear.”