Are you one of those people that leaves their horrible, dirty, horrible toast crumbs all everywhere in the butter!? What do you think when someone does this. It is horrible just think how old those crumbs are, from someone else's toast from who knows when.
When this occurs I've started removing large amounts of contaminated butter and throwing them away.
If you do this, please stop, just think of the consequences.
The same, in fact even more so, people who leave bits of coffee in the sugar!! That is the worst. Oh my god. It's horrible.