Self-inking stamps solve an issue that is presented with pre-inked stamps in the most elegant and sophisticated way possible. They don't create a mess, they aren't hard to handle, and are particularly useful if you have a toddler or kid roaming around with potential access to your stamp, this is so because try as they must, when they do get their hands on the stamp the kids can't possibly case as much a problem as they could have with a dish of ink ready for them to put their fingers in and create an inky travesty for you to clean up later. This is so because the ink plate or ink cartilage is inserted into the stamp and is not that easy to access, this however does mean that when it comes time to change the ink cartilage one might become a little worried as to how to properly do it without creating a mess. Let's look at the proper steps that need to be followed for most self-inking stamps out there: 
Step 0: Do not change the cartilage unless you need really need to:  
The ink cartilage is set precisely inside the stamp as it should be simply because there is no need for it to be constantly taken out and inserted back in. You should only remove the cartilage in case you really need to. These circumstances include when the ink runs out, when you need to change color or when you no longer plan on using your stamp. 
Step 1: Lock the self-inking stamp:  
Locking the stamp is one of the most secure ways of making sure you do not create a mess. Ink can leave a very tough stain to remove therefore it is essential for you to lock the stamp in place by slowly pressing the buttons on the side of the self-inking stamp in unison. After locking the stamp, make sure you try to press the stamp to make sure the lock is in place. 
Step 2: Carefully push the ink cartilage at one of either side: 
After placing the lock you can now safely start removing the ink cartilage of the stamp. One method would be to push the ink cartilage right at the dead center of it but this can risk spreading ink of the cartilage by accidentally pushing it out completely and it falling down. What we recommend is you push on either side of the cartilage and let it slowly "poke out". As soon as one side is completely out you can slowly start pushing at the other side till there is enough room for you to take it completely. 
Step 3: Unwrap the new cartilage and insert it: 
It would not be advised to open the new cartilage until you are ready to replace it with a self inking stamp. This is so because of the usual threat of ink being spilled all over the place as well as the ink being exposed to direct sunlight or water, ruining the cartilage. As soon as you remove the old cartilage, unwrap and insert the new one by placing it into the slit and pushing it at the center with your thumb, make sure you use your fingers to close the back opening so it doesn’t pop out.