Sometimes the mascara is too old ... even Maybelline new from the bottle can be old and clumpy.
Don't buy mascara on sale; it's usually old. Smell it; newer mascara has a very light scent that's usually a little like coffee, but old mascara is really strong.
Brushing the wand against the tube can also MAKE it clump ... just think, it's stuck at the top of the tube, and the wand has to travel through all that mess to get out, and it will pick it up!
I am not a fan of Maybelline mascara myself, though I've used it. The regular Great Lash stuff just doesn't do it for me. I use Revlon's mascara, but I've also used some of the cheaper ones, and I think they're often just as good. I think it is JANE that has the double-ended two-color/two-step mascaras? The most common color I've found is red, sometimes there's gold too ... that was the best mascara I've ever used and it was a cheap brand. I wish I knew exactly what it was.