I've got the Bohning Seal-tite a silicone based product which is recommended for synthetic strings but it just doesn't seem to really be absorbed by the material no matter how much you heat it up by friction, and as soon as it cools it rises up off the string in clumps. The Astro Flight strings seem to be almost non-porous and so I use some Behold Furniture Polish which is milky white and a spray on liquid that seems to seep in between the individual strands. Whatever is clever.....
...obligatory fanboy statement follows...
Smarten Up and Martin Up