Chemical agents which cause protein-crosslinking would be the preferred method - you can broadly make every side-group reactive and cause them all to stitch together with anything else organic, which tends to inactivate them (makes them a big blob which can't do much).

But it's nasty stuff to work with, since it also happily does tons of damage to the proteins making up the humans applying it.

Do you have an example of such a chemical being used to effectively remediate prion contaminated environments?

Apparently not: I was thinking glutaraldehyde which is used for cleaning in hospitals but reading up the advice for prions is explicitly opposed to cross-linking agents.

Which makes sense I guess but it's also scary.

You raised my hopes and dashed them exquisitely.

Until we have better, cheaper, and less error prone methods of remediating prion diseases they're the #1 fear on my biological apocalypse list.

Destroying prions is eco friendly.

Humans need a non toxic environment. Plants, and life in general, will find a way. With, and without, us.