FREE: Vintage 1968 McCalls Needlework Interchangeable YARNS Chart

The listing, Vintage 1968 McCalls Needlework Interchangeable YARNS Chart has ended.

So hard to find a rare vintage leaflet chart measuring 22 inches by 17 inches (folds multiple times) that portraits the interchangeable yarns for 21 brands and many within that brand. The 2nd & 3rd picture, enlarged, tell you how this is done.
In the first paragraph:
"Many yarns are interchangeable and by that we mean that 2 yarns knitted by the same person on needles the same size will have the same gauge (same number of stitches to the inch). The yarns may be quite different in texture or they may be the same type of yarn made by 2 different yarn companies."
You can see the yarn companies listed in the 2nd picture. This double sided leaflet is loaded on BOTH sides.
My mom was a professional knitter in her time and used these for making clothing, and many other articles. This is quite an interesting piece of knitting craft ephemera for sure and indispensable to a seasoned and novice knitter! This particular circular leaflet came out in 1968. Several were in the envelope from my mom when a 4 cents stamp sent them all! Quite a fun vintage find! Perhaps crochet gurus will be interested too!
Please feel free to ask questions! Great vintage gift too!