Yes, they CAN (and occasionally do) smell it after it's been removed- to my knowledge. Dogs have incredibly powerful noses and drugs tend to leave at least some sort of miniscule residue/lingering odor that humans cannot always detect.
What do you have to worry if you're not carrying anything though? If a dog hits on you, and they search and find nothing, no harm no foul....right?
Depends on many factors whether you get detected or not....things such as how often you wash your clothes, how long it was in there, how often, how much, what kind, what you wash your clothes with, even factors regarding the dog itself, how good it is, who their master is, even the mood the dog and/or master is in....
Point being, there are countless factors involved in your chances, and there is truly no way to quantify them....but put short and simply- yes, they CAN. Now, will or will not is the question. Good luck bud...
-PA