When I was looking for a pond builder back in 2002. I went to a guys place in Bloomington In. that used to build ponds. He had some of the best looking old barns I had ever seen, real nice light grey and the wood looked just few years old, no rot or decay. He told me they were like 60 to 70 years old. I was amazed at their shape. I had to ask what did you do to keep them so nice, and his answer was he and several of his old farm buddies would get together every few years and spray them with 50% kerosene and 50% used hydraulic fliud after mixing the two together. He said it sure did smell for awhile and you didn't smoke around them and never had bugs. Best looking old barns I'd ever seen. PO