Once in a while, I'll go through my Junk emailbox to see what the spammers are up to these days. Wading through the pharmaceutical offerings, investment opportunities and health enhancers, I saw that Maggie Crouch sent me a message with the title "guiltily methane".
Given the presence of an adverb, I presume that "methane" is being used as a verb. That brought forth a juvenile chuckle as I imagined one red-faced Maggie Crouch furtively looking around to see if anyone might detect the "smelt she dealt". (Do not click to the link to Mr. Methane, Performing Flatulist if such subject matter is offensive to you, or if you wish to retain your perceptions of my maturity).