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2. Also, what do you call stamps that have cancels that are phrases or slogans?
To be honest, they're usually called Slogan Cancels! But if you are trying to find them on websites, try searching the word flamme (sometimes flam).
Also you can reasonably refer to them as machine cancels, since they nearly (but not quite) always are. However the two terms are not interchangeable since there are a vast number of other machine cancels which don't have slogans on, e.g. with bars or wavy lines instead.