One way to 'filter' stuff is to split stacks of your inventory and only have items you
want to pick up with no open slots in your inventory. or toggle autopickup and
individually pick up stuff you want.

Then if you're willing to use the console: removedrops
This will remove all drops from the AI and anything dropped by smelters and such.
It has a maximum range but it's kinda hard to measure the distance.

Alternatively you pick everything up and drop stuff in the obliterator or deep
water as that's supposed to despawn things faster.