Moen produces many high-end taps and sink accessories. Because these products are constantly exposed to water and pressure, lime and other deposits will build up. This can cause leaks and loss of water pressure. When replacing the hardware for a new sink it is important to to remove the old insert cartridges and replace them with new ones. There are four different models of inserts, but they are all removed approximately the same way. You will need a bit of strength if they are stuck. 
Instructions
1、Use the flat-head screwdriver to pry the top cap off of the sink handle. The cap will be on top of each handle, so there will be two in total. If you have difficulty removing the cap, you may align the edge of the screwdriver on the crease and then kitchen tap the back of the screwdriver to pop the cap off.
2、Unscrew the locking bolt that you exposed in Step 1. The Phillips screwdriver should provide enough torque (turning counterclockwise) but if you are having problems you can use a rag or paper towel to get more grip on the screwdriver.
3、Attach the channel locks to the top of the Moen cartridge. You may need to point the nose of the channel locks downwards to get a firm grip on the cartridge. Tighten the screw on the back of the channel locks to ensure a solid hold.
4、Turn the channel lock counterclockwise six to eight times to loosen the Moen cartridge.
5、Reattach the channel locks as necessary to pull the cartridge straight up and out of the tap gear.
www.tapso.co.uk
http://www.robinetfr.com/
http://www.plumpinguk.co.uk
http://www.robinetshop.com
www.grifoso.com
www.tapforyou.co.uk