Have you though about using acoustic foam as found in a recording booth? You would need to protect the foam from any oil that gets thrown.
see what I'm talking about:https://www.amazon.com/s/?ie=UTF8&k...argid=kwd-105490519483&ref=pd_sl_7avx300nw6_b
Greg
see what I'm talking about:https://www.amazon.com/s/?ie=UTF8&k...argid=kwd-105490519483&ref=pd_sl_7avx300nw6_b
Greg