https://www.amazon.com/Stans-2-Ounce.../dp/B002WY12PO
buying one of those along with a valve core remover is the easiest way to renew the sealant. You just pop out the valve core and screw that on. Then you can inject whatever sealant you want without having to bust the tire's bead off the rim. Every so many times though you will want to take the tire off and clean out the build up, stan's boogers. Slime makes a tubeless specific sealant now.