Neckties can be used as strips in a Jelly Roll project if you stabilize them first with a 2 1/2" wide strip of sheer-weight interfacing fused to the wrong side.  Trim the excess tie fabric and use the strips as you would any 42" - 45" long strip.  A "Jelly Roll" consists of 40 strips, but you can substitute a yard of silk fabric for 15 of the strips to stretch your resources.