From an older post:
"All of the thin milky protectants are just a PDMS (silicone) solution that is the active ingredient nothing else. Hence why as far as ingredients go none other are listed in the MSDS.
Some add scents, some add extra surfactant, and some add lots of water. Some being more than others. Armor all is about 20-30% PDMS, leading to high shine if applied directly to plastics but I will say heavy applications will protect more. The much vaunted Aerospace 303 if you read the MSDS is between 1-5% PDMS, the rest is water. So you're paying $16 for 16 ounces of a product that's 95-99% water. I'll buy the 16 ounce Armor All for $5 and water it down 5 to 1 and have more than half a gallon of protectant equal to Aerospace 303.
But the active ingredient is PDMS, that's the actual protectant that does all the UV protection. Aerospace 303 isn't anything special, what they've managed to do is convince people to pay a lot of money for essentially watered down Armor All. I'm not making this up either.
http://www.crossfireforum.org/forum/detail-shop/25914-303-protectant-vs-armor-all.html
There's a guy, Mike-in-Orange, who actually works for Meguiars. And he also pretty much confirms all the plastic protectants are just silicone emulsions. PDMS dissolved in water.
Mineral oil on top of being greasy does not provide UV protection, it's just a light oil composed of hydrocarbons. In fact it likely makes UV absorption worse. It's actually used in tanning salons because the thin layer of oil reflects light back in and enhances tanning because it doesn't absorb the UV.
Silicon by nature absorbs the UV. You don't need to add other types of UV protectant because it's the silicone that does the UV protection. You can buy 100% silicone spray, electricians use it to protect electrical equipment from UV too and is also used by people to protect rubber seals, same as your everyday protectants like Armor All.
So my suggestion is simply get Armor All and water it down 5 to 1, you'll get the protection of Aerospace 303 and it'll really stretch it out to be more economical than even mineral oil. And will actually protect plastics, mineral oil won't."