Hi, Steve. Welcome to DC.
There is a chemical reaction that occurs at times that will turn garlic green or blue. The color is harmless.
More importantly, boiling garlic will not make it safe for long term storage. Storing it in oil will not make it safe for long term storage.
Either buy minced garlic in a jar, mince as needed it or buy an good garlic press and press as needed.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan