Hmm, I use a silicone spray. Seems like it's not 100% silicone at all and in fact does contain petroleum distillates. It works reasonably well though. However, I think in order to achieve the best lubrication effects, the lubricant should be applied lightly. What I mean is, not spraying lubricant on the cubies directly but using something like a cotton bud to apply the lubricant on the inner surfaces of the cubies.
After application, let it dry for 10 minutes +. Even after drying, some droplets do remain and must be wiped off with a cottom bud or tissue paper. Only when the inner surfaces are totally dry should you reassemble the cube. If you don't wipe off the excess lubricant, the cube will be slightly sticky.
I worked this out based on experience lol. I remember a time when I just finished lubing my cube and it was sticky for some reason. In fustration, I dismantled the cube and wiped off all the lubricant thinking that I'd rather have an unlubed cube than a sticky but smooth cube. Well, who knows, it turned out really well after I wiped off the excess lube inside. I think as long as the silicone atoms get into the microscopic gaps on the inner surfaces, there's no need for excess atoms to roll about.