Seal Achievement in Vampire Survivors

Before you can unlock this achievement, you'll first need to unlock Banish 1 (5G), Banish 2 (5G), Banish 3 (5G), Banish 4 (5G), and Banish 5 (5G), and then actually purchase all five Banishes from the Powerups menu between runs. Once you own five ranks of Banish, you now have the ability to banish 10 times per run.

As the description says, you now need to do so. However, to clarify, it doesn't need to only be weapons that you banish. You can banish items as well. This is easy enough to do by first getting four or five weapons and/or items you want, then banishing any new ones that you don't want. If you solely want this achievement, you can even banish upgrades for weapons and items you already have. Just use banish ten levels in a row to get this achievement.