NOTE: You’ll need a Phillips head screwdriver
The sponge on your mop is held in place by 4 screws, which can be located between the rollers. To remove these screws you can either hold the head of the mop in one hand or place the mop sponge side down on a counter or table, and lean the handle against your shoulder, while you look down from the top.
If you look between the rollers -- from the top -- you should see the 4 screws. NOTE: some people think the inner screw is difficult to reach, but in reality the sponge will slide from side to side with a little hand pressure, which will allow you to reach the screws by simply angling your screwdriver a bit.
These 4 screws fit through 4 holes in the L brackets. These are black L shaped spring steel pieces that attach the sponge head to the mop -- for ringing.
Slip the screwdriver in between the rollers and remove the 4 screws from the refill. (2 screws on each side) Once you have removed the last screw the mop head will simply drop off in your hand.
Now, remove the plastic from your new refill and look for the black metal "gripper" on the top of the sponge. This gripper holds the sponge in place. On the top of the gripper you will see 4 holes on the 11" mop, and sometimes 6 holes on the 16" mop. (This is 2 or 3 on each side. Don't be alarmed if your 16" mop only has 4 holes in total, not 6. You only need 4.)
Start with 1 screw and just screw it in a little bit -- not too tight. While holding the new refill in one hand, or placing it gripper side up on the table, place the mop down over the gripper, so the gripper slips in between the rollers.
Line the holes in the L bracket up with the screw holes in the top of the gripper. Insert 1 screw in 1 hole on 1 side (doesn't matter if you do the inner or outer hold first) and screw it in a few turns with your screwdriver. DON'T make it too tight -- just tighten it enough to hold the refill in place -- then move on to the the next hole. Once you have all 4 screws in place you can go back and tighten them all down snuggly. By leaving them loose until they are all in place, you allow some flexibility to "juggle" the refill around a little to get the 3 other holes to line up more easily. Once all the screws are in place just go back and hand tighten them -- make them snug, but NOT TO TIGHT.
Now you are ready to soak your new mop head to soften and it is ready to use!