Hand wash, dry flat, when dry, press garment on the wrong side under a damp cloth using a warm iron.

This yarn might be 12ply as seen in the quote below.

quote taken from https://archive.org/details/The_Australian_Womens_Weekly_...

CHA-CHA’ by ViUawool-the basic answer in 12-ply knitting!

CHA-CHA, Villawool’s thick’n’quick-
to-knit i2~ply, is an all-wool crepe
yarn, perfect for the fashion- conscious
Isnitter. 100”,, pure wool. Wonderful-
wearing in the TOP 40 shades. It is
interciiangeable with ViUawool’s
Calypso’ die bulk-without-weight
yarn) and ‘Slalom’ (the siliconised
sports yarn). This means that your
choice of colour and texture in one ply