Flies are not the best way to go about hooking these fish, but I have stabbed countless "Garbage" fish on white, olive, brown, and black Wolly Buggers, and also on Gold Hares Ear nymphs. Any black beadhead bug should work too if the fish are hungry. Most come from the Tualatin river, or the Mac when I fish it, but they were all traditionally swung on a 4/5 wt. Some in more recent times have come on drift fished egg patterns , and other big, ugly Steelhead bugs, but that was just using a fly stick to drift pockets on the Clack, Sandy, Ump, and Santiams.