after someone I suspect is donkish calls a pfr and leads weakly, I look at it like...
1bb lead and they have a monster (very rare) or something like A high, a pair of 2s, or two overs.
2-3bb, they could have a lot, maybe just don't understand betting proportional to the pot (they got a $6 hand), or are pricing a draw. I rather raise these (sometimes call, but I like raising usually) with some kind of draw or piece, and/or a solid image.