Use the program xev through grep to show only ButtonPress events.

xev | grep -A2 ButtonPress

Create a file called .Xmodmap

micro ~/.Xmodmap

Inside the file disable and/or remap buttons you detected with xev

! Remap button 1 to 8 and disable button 8 and 9.
pointer = 8 2 3 4 5 6 7 0 0

Check it.

xmodmap ~/.Xmodmap