Firstly flush the container out before filling for the trip, if a steel jerry then pour the flush fuel out thru a mesh filter to make sure no paint chips are floating a round, I would usually just pour the fuel using a plastic funnel that has a fine mesh filter in it and a flexy spout, $5 at supercheap have used them for decades and no drama, the most important thing is clean fuel cans, I store my steel jerries with a bit of diesel in them and closed so they don't rust and with some of mine dating from the 60's and still good, I stow my funnels and hoses in zip lock bags inside a designated tool bag only opened for use, keeps crap off/inside them. You can go very ******** and get some with mini filters in them, look the part I suppose.....
I also change my fuel filters every 20K worth the effort.