captainjohn - He has not disassembled the metering needle. The pic is of the "in" side of the screen. The metering parts are untouched.

Cambo - the screen is intended to capture stuff to stop it from penetrating into the carb passages.
If you can get 'er clean, you're golden.

DO NOT remove those parts I circled in red in the photos....unless you have been there, done that.