I don't know how many times I have seen this subject come up but I keep wondering why everyone over looks the obvious and shoots straight for the overly complicated...
It is far easier to use a set of hydraulic filters in series with a low volume pump and get a absolute micron filtering of 3 micron... Which I think is way over kill but again there are absolute 5 and 10 micron spin on filters too...
2 hydraulic filters... say a 10 micron and a 5 micron... 2 hydraulic filter heads.... a low volume chemical pump (12, 24, 110V) and you have a light weight, portable recycling system which is easy to store, easy to use and easy to change filters on and well under 300$. If ya wanted to be really crafty you could plumb and mount set up right on the truck.
Why screw with bags, yes the bags are cheap... but the canisters that hold them are $800-$1000, not using the canisters gets you one big mess!!! Coffee filters... 30-40 micron with the weight of the oil? why bother, your oil filters are that! A centrifuge unit, yeah sure if you happen into one on GL or some other surplus source but for most of our luck hitting the right 6 digits on the lottery is more likely...
Im not trying to knock anyone... I just don't get why good old KISS (keep it simple stupid) is always being over looked on this subject.