Cocker spaniels have long, floppy ears that grow long fur, making them an ideal location for mats to form. Mats form when the fur becomes tangled. If the tangle is not quickly brushed out, dirt, loose fur and other debris becomes trapped in it. This causes the tangle to become wound tight, forming a mat. Depending on the mat's severity, you may be able to brush it out. If the mat is too tight, the only option is cutting it out.
Lift the ear away from the cocker spaniel's face with one hand. Spray the cocker spaniel's matted ear with an oil-based conditioner until it is saturated. The conditioner penetrates the mat and helps loosen it.
Hold a mat splitter on the ear. Drag the splitter down the ear and through the mat. Go through the mat multiple times in different locations.
Brush through the mat with a slicker brush from the ear's base to tip. If portions of the mat remain, go through them again with the mat splitter. Then, brush the cocker spaniel's ear with the slicker brush once more.
Comb through the ear's fur with a grooming brush once it appears the mat has been untangled. If more mat is found, go through it with both the splitter and slicker brush again.
Cut the mat out with a scissors if the splitter cannot go through the mat. Hold the cocker spaniel's ear away from its head. Open the scissors and push one blade through the mat, perpendicular to the dog's ear. Cut through the mat and repeat until the mat has loosened.
Slide a thin comb between the mat and the dog's skin once the mat has become loose enough. Cut the mat out with a scissors, using the comb as a guard so you do not cut the cocker spaniel's skin.
Brush your cocker spaniel's ears frequently to prevent mats from forming.