I use blaster silicone spray... I dont think it provides more spin than new strings but it does prolong that feeling. My current Poly/gut setup is at 17 hours and it is actually slightly spinner than when I first had it strung because it has a lower tension now and a broad string tension disparity. The gut makes up for the poly's deadness.
Extreme Eastern BH, Pacific x Feel Pro 95 12.83oz 9pts hl, Head IGPMP 13 oz, 9ptsHL, 1 Max 200g, 1 Becker London Tour