How do you open a 3 digit Buffalo combo padlock that you can't remember the combo to and reset the lock combo?

Hold down the silver button on the side. Scroll through the far right wheel until you hear a click. Do the same for the middle and left wheels. Hope it helped!

(Worked for me)

Update: Use your thumb to hold down the silver button on the side. With your thumb, you can feel the button "fall" or "bump" into place as you turn the wheel to the correct digit. This usually works really well on the 3rd digit. This at least narrows it down to 100 possible combinations (rather than the original 1,000). Or, knowing the last digit may help jog your memory to remember the combination you set in the first place.