An article by a sail boater in the Caribbean who would leave his used diesel oil on the dock for the locals to use, and this forum has gotten me to thinking. Given the following: 1. The vast pre-ponderance of 3000 mile OCI doityourselfers. 2. The strong possibility that an oil filter is good for 10k miles. I wonder, if an individual went to their local recycle center with a siphon pump and "borrowed" five gallons of used oil and a couple of filters (to be returned), is there much liklihood they'd be doing any damage to their engine with 3000 mile OCI and filter intervals? Personally, I'd probably strain the oil through an old T-shirt first. Just wondering, anybody ever do a used oil analysis on oil found in the recycle center oil tank?