Empty the bottle of oil into a saucepan.
Add the rosemary, thyme, basil, and garlic.
Bring the oil it a boil and then reduce the heat to a simmer.
Simmer for 10 minutes.
Remove from heat and let cool completely.
Once cooled, put a strainer over a bowl or a measuring cup with a lip. Pour oil through the strainer and let strain.
Once strained, discard the herbs and garlic. Pour oil back into the olive oil bottle and close.
Remeber to put a label on it.