When feeding someone by g-tube for medical reasons, it is important to clean the extension tubes and the syringes that are used. If food remains in either place, it provides a perfect environment for bacteria to grow – definitely not good!!
Clean soapy water in the kitchen sink, just like doing dishes, works well. Using the largest syringe you have, pull back on the plunger filling it with the soapy water. Push that soapy water through the extension tube and then pull back on the plunger while still connected to the extension tube. Do this a few times, opening any ports that are part of your extension tubes.
Then look in the largest opening on the extension tube for any debris left behind. A toothbrush works well in that opening. Also check around the end where the extension tube connects to the g-tube itself. That area can also be cleaned with a toothbrush dipped in the soapy water. Rinse well, set in a bowl or basket lined with a clean cloth. Put the open ends down so that water can drain out of the tube.
To finish washing the syringe, take it apart and using a clean cloth in the soapy water, wash the rubber end of the plunger, also the outside of the syringe. Swish them around in the soapy water to help remove any residual debris on the plunger. Then using one of these
handy items,
which are actually designed for cleaning computer keyboards, dunk it in the soapy water and then use it inside the syringe to get the inside of the syringe as clean as possible. 
I also rinse the syringe and plunger with very hot water.
Rinse well and reinsert the plunger. Turn over once or twice to let excess water out of the two ends of the syringe. Then place in the bowl or
lined with the clean cloth, with the tip of the syringe on the fabric. This will help any water left in the tip to wick out onto the cloth. A dry syringe and tube are less likely to grow bacteria than a wet one.
It is important to reinsert the plunger because rubber oxidizes with contact to air (and light) and then the plunger will not fit into the syringe after a while.
Put the basket or bowl in a cabinet for storage and protection.
Pedaling Backwards 
What do you DO, when the plunger will not deploy? I am using this type of syringe for my cat who has a feeding tube, because of Pancreatitis, and these types of feeding syringes seem to lock up and won’t plunge after a few uses. Horrible to try and hold a cat, all the while trying to wrestle with a syringe full of food or water that won’t budge. Poor cat, poor me.. its frustrating.. Do you have any metal or resuable feeding syringes or know of any? Thanks for the info…
Daria, I know the frustration. The best solution I’ve found is to drench the rubber area of the plunger in some type of vegetable oil. If you do it right from the beginning of using the syringe, it will keep the rubber from oxidizing and expanding (at least that’s what I THINK happens). I typically use just a few drops and that works, but I have had times of extraordinary frustration where I have just drenched it and that has helped. I don’t know of metal or anything. Syringes used to be glass… I cannot imagine having to worry about glass breakage on top of everything else. Best of luck with your Kitty.
~Lynn