Played legit back during the original CoD 4 for the golden Dragonov and the Golden Uzi.
Played legit in WaW with the exception of some glitches to get in weird spots on the maps (not under the maps though, because that it is just unfair).
Played legit on BO3 to get to level 288 Prestige Master in Zombies.
Other than that though, I never grinded hard to get camo's or anything.
I played legit on all CoD games except for boosting for one camo on MW2 because a friend wanted it. I've modded on other CoD games for fun or to just mess with all weapons and attachments on random accounts.