Barry,
When you're typing the reply, there is a tool bar at the top of the box. This enables you to
change fonts, change type size, change colors, insert smilies
,
make your type bold, put it in italics, underline it, etc.
The last icon on the right is
ABC.
Highlight the words you want to cross out. (Click at the beginning of the word. Hold the button down while moving the cursor. Let it up at the end of the word.) Then, while the word is highlighted, click on the
ABC box.
Edited to add: Use "Post Reply," not "Quick Reply."