Step 1: Un-twist and separate half the plies (or as close to half as possible) on the end of one of the yarns for about 4 inches (10 cm), then do the same with the other end of yarn to be joined.
The example shown is a 2-ply yarn. One ply has been separated from the other ply. If your yarn were composed of 3 twisted strands (i.e. a 3-ply yarn), you would separate two of the plies from the other ply. If your yarn were composed of 4 twisted strands (i.e. a 4-ply yarn), you would separate two of the plies from the other two. And so on for yarns with more plies.
Step 2: Break off a 4 inch length of separated ply(s) from the end of each yarn.
In the example of the 2-ply yarn shown, one of the separated plies has been broken off each yarn end for a total of 2 strands remaining on both yarn ends.
If you are joining a 3-ply yarn, you would break off the group of 2 of the plies from the remaining ply; on the other end you would break off 1 of the plies from the remaining group of 2 plies. This gives a total of 3 strands remaining on both yarn ends..
If you are joining a 4-ply yarn, you would break off a separated group of 2 plies off each yarn end for a total of 4 strands remaining on both yarn ends.
Step 3: Lay the remaining separated plies of each yarn end side-by-side and in opposite directions across your palm.
Step 4: Slightly moisten the area to be joined, and briskly rub your other palm back and forth across it until the fibers re-twist and lightly fuse together. Because the total number of separated plies was equal to the number of plies in the rest of the yarn, the result after re-twisting should be a uniform thickness across the join.
Step 5: Let the joined yarn area dry, then proceed with your knitting.
