Full Chemical Protection is a skill that protects the equipped weapon, headgear, shield and armor of a single target from damage and removal temporarily. This does not protect accessories, so do not rely on them when setting up a build. Each cast consumes a Glistening Coat.
You can purchase Glistening Coats (10,000,000 zeny) from the Alchemist Dealer (moonhaven 173 178) at the mall, which is on the left side of Moonhaven. You can trade in one Platinum Coin for 2,000,000,000 zeny at the Coin Trader (moonhaven 199 193) using this process: Coin Trader > Purchase Zenies > Platinum Zenies. Then open your inventory and find the Platinum Zenies. Open it, and you will automatically be given 2 billion zeny. You can now purchase 200 Glistening Coats.
The skill is normally available to biochemists, but other classes can also use it if they have equipped Elite Glasses or their path's middle headgear, which enable Level 3 Full Chemical Protection.