Here's a quick way to test a new CSS style without commenting the entire code block out. Just place an "x" before the style you don't want to show. That's it! Just be sure to remove the "x" before uploading your final style sheet as this can cause conflicts with other scripts.

Normal style (no commenting):

#someDivStyle {
    font-family: "Helvetica", Arial, sans-serif;
    font-size: 1em;
    color: black;
}

Regular commenting style ("font-size" is commented out):

#someDivStyle {
    font-family: "Helvetica", Arial, sans-serif;
    /*font-size: 1em;*/
    color: black;
}

Quick commenting style ("font-size" will still be commented out):

#someDivStyle {
    font-family: "Helvetica", Arial, sans-serif;
    xfont-size: 1em;
    color: black;
}