oil filter magnet

[SteveO_71]

I've seen magnets as part of the oil pan drain plug but wasnt aware of magnets for the oil filter.

Do these work or is it a mixed opinion? I realize the filter will collect a lot of the contamination but would a magnet collect whatever is left flowing around? Seems like it may be beneficial for an older car engine that may have lots of ferrous metal parts.

thoughts??

http://www.shopfiltermag.com/product/ss-365/

 

[midlife]

I'm surprised that it doesn't claim to increase your gas mileage by 50%.
Filters are designed to filter and retain particles. Why would you need a magnet?