How Can I Build an Effective Creeper and Witch Grinder?

[emileekaiser]

Heya. I've been trying to build a creeper and witch grinder for the past week and have tried everything. Nothing is working and no videos online have helped me. I currently have one that makes them fall 64 blocks but they just won't die.Can I get some suggestions? Below are a couple pictures of my current "grinder". Thank you!

 

[FractalCake]

Heya. I've been trying to build a creeper and witch grinder for the past week and have tried everything. Nothing is working and no videos online have helped me. I currently have one that makes them fall 64 blocks but they just won't die.Can I get some suggestions? Below are a couple pictures of my current "grinder". Thank you!

Are you using the spawners from the swamp island? Those are very high level and would require a longer drop than 64 blocks.

If the mobs aren’t dying, it’s not high enough.

 

[FuriousCorgi481]

My suggestion is (works best on coop) a fully automated death machine. Use all of your balance on items, and then build a bed. Use blocks and water to throw you into the grinder. Creeper explodes, drops gunpowder. Grinder complete.