If you are worried about the corn cob leaves (when doing Tangwena's Malawi fermented cob technique), then simply use oven baking (parchment) paper instead as it works great.
This type of paper is durable, so much so I sometimes even reuse the same paper for wrapping cobs when I run out.
If you are developing mold when cobbing with natural leaves (or parchment paper) and vacuum sealing then the cobs are too moist when sealing them up.....so dry them out for a little longer after the initial sweating stage to induce fermentation and again before you re-seal for the long term cure.
and I'm not corn farmer but aren't corn crops sprayed with weed killer when the corn has just started growing? I don't think corn is sprayed with poison when the cobs are forming? ...any corn farmers here? The leaves from around the actual corn cob weren't on the plant when initially sprayed so the amount of poison you are getting into your Malawi style cobs is miniscule. If you eat corn, then you are ingesting that poison but smoking a tiny bit of cob at a time is not a concern really. (unless you are the hysterical type who freaks out and amplifies selected info)