BooKIT Joomla 1.5 nth-of-type Select option

Question

I have an old website using Joomla 1.5 and a booking componant called BooKIT. My customer asked me to remove one of the booking items but there seems to be no way to remove them. A form shows all the booking items in a Select option box. Because there are no traces of these values I am trying to hide some of the HTML option values with CSS but the following code isnt responding:

*Using nth-of-type - not working*
select#filter_catid option:nth-of-type(2) {
display:none !important;
}

*Below the CSS already in use that works but not selecting nth*
select#filter_catid {
       font-size: 2rem !important;
    background-color: #B9B695 !important;
    color: aliceblue !important;
    border: double;
    border-radius: 15px;
    padding: 10px;
    margin-left: 50px;
}

Answer 1

Problem solved.

I recalled that when changing anything in early versions of Joomla I needed to clear my browser cache to see any changes made.