When I looked at them they seem to have some kind of grey compaund, and a lot of it all around them. I don't know if regular white or black silicone would be as strong as the stuff they use at the factory. IT would have to be able to withstand extreme heat and cold conditions, weather conditions, and the test of time. I really wouldn't want to redo the silicone every few months or even every couple of years, and the one that is used seems to be very long term. I mean, if I have to boil it to remove it, it has to be pretty darn strong and durable, wouldn't you think?