Sounds like Jethro's pollution solution.
Season 8, Episode 25 – Aired: 3/11/1970
Honest John Returns
Jethro and Granny come home to tell Jed and Granny that they saw Honest John, but never caught up to him. He heads to his wife's house to tell her what happened. When he tells her he's turned straight, she gets mad and threatens him. But after a while, she tells him to go and con the Clampetts. He realizes how they live in L.A, and visits them. He tells Jed he plans to rid the smog by drilling a big shaft in the San Bernardino mountains, put a fan in there, and suck the smog out. Jed says that he will put up the money for the project. When he visits Drysdale, the banker refuses to let him have the money that can be spared unless he tells him what it's for and where. Jed tells him he is going to be drilling in the San Bernardino mountains, and Drysdale thinks he found oil, and plans to buy the land up there. Jed heads home and gives the money to Honest John. As he is about to leave, Elly and Jethro come back, and they get told Jed's plan. The clan thanks Honest Jed, and their sweetness gets to him. Jethro is told to drive him anywhere. When Shifty gets back home, he tells Flo the plan, and she asks where the money is. He tells her not to worry, and when she says she likes to worry and to tell him, he says he gave it back. Flo tells him to come to her arms, not to get romantic, but so she can break every bone in his body.
I have to post this link again:http://www.drroyspencer.com/