I've had very good luck with Goo Gone Spray Gel. Note specifically the gel product, not just the regular liquid. For whatever reason, I found it works better. I found it at Walmart, but I'm sure available elsewhere.
To the OP, I assume you mean cured vs. uncured? It may not work as well for cured. I did find that during assembly, before the silicone is cured, the referenced Goo Gone Spray Gel really knocks down and thoroughly cleans the uncured silicone. I use it to clean as I go during assembly. Works great. Many other products leave smudges behind or you have to wipe over and over.