Mold can indeed be very ,very dangerous. Throw it away. Smoky smell is gross, hard to get rid of, and can also set off some terrible asthmatic attacks. Throw it away. Charity, by definition, is LOVE, but is giving something MOLDY to ANYONE (to fix, wash ,or use) a loving thing??? Smokers can't usually tell how bad fabric smells; they've become desensitized. But I get nauseated by it. My cousin can be hospitalized if she accidentally inhales second hand smoke.
As for dirty, that could range from slightly dusty to downright disgusting . Giving something dirty (regardless) is also NOT charitable (unloving). I would think about how the recipient would feel to receive anything that even hinted of gross, dirty, stained, or smelly. I hold to my motto that fabric has no feelings, but people do. And for people who have the audacity to "donate" gross looking or smelling things, they either will never know you threw out of their stuff, or if they do, they might learn a lesson. I don't mess around when it comes to this subject.