The filter would already trap those metal shavings anyways. Keep in mind, any filter on the market is going to catch pretty much 100% of the particles that are 40 microns or bigger. You can't even see a 40 micron particle with the naked eye, that's how small it is. 100 microns is the cross section of a human hair.

So in other words, filter magnets are useless.

 

Patman, it seems metal would be caught by the filter but I have noticed that on some engines with magnetic drain plugs there is still metal that is stuck there when an oil change is done.

 

yep, i can vouch for the post above, my 01 S10 quadcab with the 4.3 Vortech has a magnetic plug and there is metal shavings stuck to it at oil change time.