I am going to give you some tips on how to clean your pads. I have tried every way possible except running them through a carwash. Here's what I found out:

Hand wash

In a sink, preferably with the hottest water available and dish soap, let them soak for half an hour. Agitate the pads every ten minutes while they are soaking. If the pads smell really bad, let them soak for a couple of hours. Once they are done soaking you must let them air dry, preferably outside during the day. You can try it at night, but you will find the pads may still be wet in the morning.

Dishwasher

Strap the pads onto the top shelf of the dishwasher, use regular dish washing liquid, and start the dishwasher. This works good, except when they are done washing they will still need to be air dried outside.

Washing machine

The washing machine is not the best choice for pads, but it will work. Inexpensive pads tend to fall apart in the wash, so use caution if you choose to use this method. If you use the dryer make sure to throw in four or five towels with the pads. This will keep the noise down and keep your pads from being damaged.

When washing your pads make sure the Velcro is firmly attached so that the straps don't tangle in the machine. If you find that the smell is still there, use vinegar. I recommend soaking the pads in the sink with vinegar and water if the odor remains after they have been washed in the dishwasher or washing machine.