Using used vegetable oils for preserving wood structures in the garden or farm

  Recently on letgo software a neighbor had 16 gallons of used rancid peanut oil to give away. She advertised it for a while and i collected it. Having already used corn oil successfully for wood preservation of a pine structured cage i built over the raised veggie bed. I thought the peanut oil would work well to help restore a variety of wooden structures around the  large garden. Its a thick oil and when applied, gets sucked right into the several year old wooden objects that have been bleached grey in the Californian sunshine. After a couple of days all the greasiness disappears and the wood goes darker and looks much younger. I am sure that this oil will make the wooden railings benches and raised veggie beds look and live for many years longer before cracking up into disuse. As an ex professional painter i realized that many wood preservers at Home Depot though effective are wildly over priced for basic yard based objects.And i urge others to explore used vegetable oils for  wooden garden items. I used it on bare wood fences, old benches, posts and wooden veggie beds as well as small wooden bridge over a stream. The color of the wood is also a nice rich dark brown instead of the old grey.

That's great! We use old rancid/oxidized vegetable oil as part of the process of burnishing unglazed pottery made from our native clay, and it works well for that, too. The oil burns off in the firing.

Good tips. I will give it a try. Thanks.
I used to send used and filtered cooking oil to a local shop. They burned all kinds of oil for heating in winter.

Where does one acquire used vegetable oil? Why would someone have a bunch of it sitting around?

Those who use deep fryers, including turkey fryers, at home inevitably have used vegetable oil. Restaurants produce lots of it. I used to collect it for the biodiesel co-op in Portland, Oregon from small restaurants and bars who were willing to put their used oil in empty five gallon totes-- the ones the fresh oil arrived in.

Thanks folks for the use suggestions! We still use a deep fryer.

We use old vegetable oil on all our outdoor wood.  It works better than paint or varnish.  The sun here dries  everything thing out in no time.  

Thank you for suggesting the use of vegetable oil.  Seems like a great nontoxic, or less toxic, substance to use on wood.  Are there any downsides?  Does the rancid smell dissipate eventually?

I know that rancid oil is bad for humans. Its probably the rancid compounds that is deterring/killing the decomposers.    

We use old oil on wood garden tool handles and on the steel as well. The oil we get is from the bulk dispensers at our food co-op - the dredges that they don't get drained from the containers. Free and not rancid at first, but we keep a gallon in the shed and just add to it so it's several years worth of accumulation. Much better than the old "recommendation" to dip tools in a bucket of sand wet down with used motor oil (with all of its toxic contaminants).