i use a filter straw(seychelle pure water advanced filter straw is my current model,there are others but not quite as good) doesn't matter what container i dip or what i'm dipping from the straw handles it. i've even been known to drink right from a dirty shallow puddle with my straw,just to prove the point.never had any adverse effects.i love filter straws.the straw filters virus and bacteria down to 99.99% with the advanced filter,which has added iodinated resin in the filter. i don't leave home without the straw,ever.comes in a handy clip on storage tube for under $20 and filters 25 gallons of water. i also have their 2 liter pouch that will filter 100 gallons down to 99.9999%. i use this to gather bulk/cooking water,and squirt it out,filtered,into my pot or stainless bottle,it rolls up,stores almost flat and weighs about 1/2 lb.i carry a 40 oz wide mouth stainless klean kanteen,i can fill my bottle 80 times per straw and never have to pump,wonder if i used the right amount of chemicals,carry extra containers(except my 2L filter bag),boil,etc.,etc.etc. my whole kit(kanteen,straw,bag) weighs about a pound and will produce 125 gallons of 99.99%(minimum) filtered water from ANY source other than salt water,beat that.