The Norton disposable paint cup eliminates the problem of gunked up threads because each unit comes with a fresh set of threads. The only reusuable component to keep track of is the hard mixing cup with pre-printed measurements, so there are no inserts to keep track of either. The unitized Lid/Liner assembly is guaranteed never to come apart during disposal which eliminates the hazard and mess of spilled paint. Or, it can be securely sealed with the plug for use in future spraying of the remaining paint. No matter how you handle it, the unitized leak-proof Lid/Liner assembly is guaranteed to remain securely sealed during disposal or storage. It’s as simple and as ingenious as that.