yes, I know Dana K. White would say decide which pens to get rid of, but for now I have space for another mug and that's easier than making more decisions

Haha, yes! It's OK, she says that you can keep extra containers if you have space for them. Although in the long-term it is of course worth thinking about how many pens you really do actually need / want / use - I have a huge pencil-case full and in all honestly only spend about ten minutes a week writing... probably most of them should go...