Originally Posted by vwnate1

You want to place a magnet in any thing lubricated by oil because it collects the normal "SWARF" ~ this is tiny bits of ferrous metal that's left over from the initial manufacture and from normal wear and tear ~ by removing it from the oil it reduces wear significantly .

There was a time when most drain plugs were magnetic .

I add two magnets : one to the drain or sump and another to the fill plug .

The drain / sum one collects rough SWARF , the filler plug ones collect much finer particles .

It's another of those little things you can do to maximize the life of machines .