Overtime, any coleslaw is going to become a bit more watery because shredded cabbage releases moisture. If you'd like to meal prep your coleslaw and make it last as long as possible, you may want to take the extra step of salting your cabbage to draw out the excess water before using. After shredding the cabbage, sprinkle it with a generous sprinkle of salt and let it sit for about an hour. Then, rinse the salt from the cabbage and place the cabbage on a clean kitchen towel. Ring out the excess water, then start the recipe as usual.