ha, I know what I'd do. 

After I've cleaned a tip several times, and or I've gotten it (the tip) super hot a few times, I don't mind using it for a while longer until I start a project where things need to be cut clean, -- then I buy a new tip and, crisp clean cuts again.

It seems to me the tip cleaner has a way of distorting the holes, an this in turn creates the 'swirl' I referred to above.