Stuff sticking, looks like webbiness precursor to mites to me...
Better safe than sorry? Neem and dawn, or just warm water and dawn, make sure you hit the undersides of all leaves and the top layer of soil as well as the exterior of the pot.
you'll see the mites crawlin' around if that's what it is. if you look at cannabis under a microscope the entire plant is hairy as fuck, like a sasquatch. so it might just be collecting dirt.
Partly looks like dirt on the bottom of the first one but those pinhead black spots dont look great. Post of pic of the top of the leaf. Also, If you take the leaf and look at it very closely and those are mites you will see them move around. Also if you see anything that looks like webbing (like spider webs), you have them.