I frequently call out waste yarn in my patterns. This is just a substitute for a stitch holder. Personally, I don't use stitch holders.
Using Scrap Yarn Instead of Stitch Holders - PurlsAndPixels
Knit with Henni
Ravelry: Mediterranean Scrub Set pattern by Jill Wolcott
Using Scrap Yarn Instead of Stitch Holders - PurlsAndPixels
magic Archives - Jill Wolcott Knits
tutorial
Slip, Slip Stitch, Slipped Stitches - Jill Wolcott Knits
Knit with Henni
Parts of a Stitch in Knitting - Jill Wolcott Knits
Knitting Tutorial - How to use 'waste yarn' for holding live