Could you add a recipe to void blocked slots? Doing it by hand is tedious, especially given it stacks to one. With a recipe I can just stick an assembler on the end of the belt to clean up for me.

The blocked slot item should only need to be manually voided when you accidentally took them out, so I did not think they need to be voided in bulk. Cluttering the recipes interface with an entire recipe dedicated to voiding an item that is frankly an implementation detail that's best not interacted, sounds unideal.

Not to dismiss your situation, but to figure out a better way to handle this, may I ask why you why you need to void them in bulk?

I changed my setup because fruits were being over-harvested and flooded my belts with them. And because fruits were backed up at the time, I didn't notice until the blocked slots were everywhere.