If you’re running outside, your shoes come across everything from mud and puddles to leaves and grit. All of this dirt can make your shoes look worn out before they really are. So once in a while your shoes just need a makeover.
Wash the sockliner or insole separately if you’re able to remove them.
Remove surface dirt such as mud and grit. Use an old toothbrush, a little warm water and a gentle soap. This should take care of the dirt.
Dry your shoes naturally and don’t place them near a radiator. Direct heat will alter the shape of the shoe. Open out the shoe and then stuff the inside with kitchen paper or newspaper. The paper will absorb the dampness inside the shoe. A shoe takes about twelve hours to dry out.
Source: www.asics.com