silicone is fine. for people who have moisture in their lights...it might be because they're sealed too much. i was messing with my grandma's car the other day cause it had 1/8" standing water inside. took the bulb out...pshhhh...pressure like opening a soda bottle. took the light out, drilled a few small holes in the bottom, and the moisture is almost gone off the lens. even sealing the crap out of a headlight lens doesn't mean its sealed. theres still air getting through the bulb sockets, especially around the 9006 and 9005 bulbs. those rubber boots are NOT airtight. think about it...water needs to evaporate. water getting in through the top (for example) needs more sealing. residual water on the lens means it needs more ventilation. another reason ebay headlights "fail" and fog over is the lack of ventilation.