Snappy Clean keeps for about a week in a bucket, depending on use. If you've only washed one or two pads in the bucket then you might be able to make it last a little longer.
I soak my pads in the bucket for a day or two then take them out and rinse them. Once I've rinsed them, I put them on my Flex and spin at about 5 or 6 and use a nail brush to clean the pad while it's spinning. I'll inspect the pad and if it's still dirty I'll use the brush until I get the pad clean then let it air dry. Also, get large zip lock storage bags to store your pads. Write the date used and type of polish used on it as well.