Some bbs could use a washing, but when they are bio, its important you plan on using them right away.
some off major brand bb's leave a white dust, especially the ones that come in bags.
I recently switched this newer brand, called Killer Bee , they seem to very good, they feed well, and shoot pretty accurate for me . I use them in my sniper, pistol , and p* 416 . I shoot a alot and never had one issue.