Using a brita filter is a bad idea because alcohol will denature the plastics in the filter and put more impurities in your vodka.
If you want to purify cheap ass vodka into swill that's more drinkable, pour it into a larger glass bottle with a handful of activated carbon and let it sit for a day or two, then filter it out with a coffee filter or something similar.
If you want to purify cheap ass vodka into swill that's more drinkable, pour it into a larger glass bottle with a handful of activated carbon and let it sit for a day or two, then filter it out with a coffee filter or something similar.