It's that time of year again, to start making up your fish oil for next trapping season...so I am bumping this post up for those who may be interested in making their own sun-rendered fish oil.
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I have seen that this is an often asked question at trapping forums that I go to.... So, just in case anyone wonders how it's done...here is how I make it.......
In the summer when it's pretty warm to hot, I'll take something like an old clean plastic one gallon milk jug, the kind with the handle. I will cut up my fish into chunks small enough to fit into the jug, and fill it not over 3/4 full. Then I drill a hole in the center of the lid, and screw it on the jug. I then stick a small plastic hose into the hole in the lid, but only letting it stick in a couple of inches...You want it to be well above the fish. Then I use silicone or epoxy to seal it in place and seal up any leaks where it sticks thru the lid. I also run some around the lid where it screws on to make sure the entire jug is sealed air tight.... I then tie a cord to the handle and tie a smaller bottle or jug to this cord, allowing it to hang maybe a foot below the milk jug of fish. I fill the second bottle or jar with water, and stick the free end of the hose into this bottle, running the hose end into the water and clear to the bottom. I put no lid on the second jar or jug, and I check it occasionally and make sure it stays full of water and the end of the hose is still under water at the bottom... The gas that forms in the jug of fish will be vented off thru the hose, and with the end of it being underwater the flys can not get to the fish to lay eggs... I then tie another cord to the milk jug handle and use this cord to hang the whole mess out of a tree(and away from the house) where cats, dogs, ect., can't get to it... Let it hang until the solids appear to settle out to the bottom and it has turned to liquid. This may take a week or several weeks, depending on the temperature... Now, the oil that forms on the top is the actual fish oil, and has a milder odor, and can be skimmed off if desired,(Some people use a turkey baster to "suck" this oil up and then squirt it into a jar or bottle.) but most people just use all of the juice, calling it fish oil... I then strain it all thru a cloth into a bottle or jar and discard the solids that strain out... The liquid is the fish oil(fish juice).... Now there are several ways to do this, but this is the way I generally do it...and "meat juice" can be made the same way.... However.... I have read that some people make a kind of "fish oil" by mixing clam juice into cooking oil. I have not tried this, but they say it works well. In a setting close to other houses, or with neighbors close by, this may be a better(and more neighbor friendly) approach to take to makeing your own fish oil.
*NOTE.... If your wife/mother/husband/girl friend/boy friend/significant other/slave/personal chef/cooking class/meals-on-wheels sponsor/ect., cooks with canned mackrel or salmon, you can drain off the juice and save this to use as a sort of "fish oil" also. I drain it into a plastic squirt bottle, and I also drain the oil from sardines (the sardines in oil, NOT with mustard or hotsauce)and from canned oysters and clams, ect., into this same bottle to use as a lure on the coon line. I shake it up good before useing.
*NOTE 2.... I have been told that Oriental Food stores sell a type of fish oil/fish sauce for cooking that is called "Patis", and some trappers have begun to use this as it appears to work well, is already made, and is realitively inexpencive... But I have had no experience with this product personally.