Step 1
Place all of the packing foam that was around the new Blanco sink back into the box. If you do not have the original box, place a thick blanket on the floor. The bottom of the sink must be cushioned to avoid damage.
Step 2
Position the sink right-side-up on the box or blanket. Find the two white dot stickers. These stickers indicate the centers of the knockout holes. Look under the sink to ensure the dots are on center of the knockout holes.
Step 3
Hold the back of the sink near the knockout hole with one hand. Tap the white dot sticker with the round end of a 6-oz. ball-peen hammer. Do not hit hard; simply tap it a few times until the hole pops out of the sink flange and into your hand.
Step 4
File the inside of the hole lightly with a fine file to remove any burrs.