termination indicator and apostrophe s

I have recently had to braille the abbreviation CFC's (stands for chlorofluorocarbons). I know the 's' after the apostrophe is not a capital letter so I used the termination indicator to indicate the end of the double capital sign I used at the beginning. I wondered where I should put the termination indicator: Do I put it before the apostrophe, or after the apostrophe but before the 's'. I was putting the termination indicator right before the 's'. Just wanted to verify if I'm doing this correctly. Thanks.