Beetling

Beetling is the pounding of linen or cotton fabric to give a flat, lustrous effect.

Within Ireland, beetling was first introduced by Hamilton Maxwell in 1725. Beetling is part of the finishing of the linen cloth. The hammering tightens the weave and give the cloth a smooth feel. The process was gradually phased out, in lieu of Calendering. A similarity is the compression; however, with Calendering, the finish does not remain for the life of the cloth. This distinguishes it from Beetling.

...
Wikipedia