If you've discovered some dishwasher cleaners in the back of your cabinet, you may be wondering if they have an expiration date. As a general rule, dishwasher cleaners lose their effectiveness after six months. The majority of dishwasher cleaners, including Finish dishwasher cleaners, will have a date of manufacture printed on the product, but not an expiration date. As dishwasher cleaners technically do not expire, expiration dates are typically not printed on packaging.