Don't throw those dying markers away just yet - they're perfect for adding texture! The amount of ink that comes from them is uneven (and unpredictable) and creates a textured look without even trying. They're also great to use for a subtle background, to lightly sketch out a drawing, and even to add subtle shading and shadows.
So instead of dumping all those less-than-perfect markers in the trash, wrap a piece of masking tape around them (so you know they're "special") and put them to good use.