Filofloss silks were made by Pearsall, who now produce Filoselle silk, from the 1920s to the 1940s. It is a low-twist stranded thread with a high lustre, and has a lovely smooth feel. You will of course not be able to buy any other shades, but if you would like to try stitching with silk, just to see if you like it, you could use some of these for a small design. The silks are wound on the original cardboard bobbins (see picture below).
I have the following on offer (postage 29p for a second class stamp

a set of three greens, 90p
a set of two greens, 60p
another set of two greens, 60p
yellow, 30p
beige, 30p
bright green (2x), 30p
(postage for two sets is quite likely to still be 29p as they weigh next to nothing)
