I have been using coupons for quite a while but just recently starting getting Kroger home mailers with coupons. I'm a casual couponer so I need some help with the Kroger coupon mailer. The coupons say "manufacturer's coupon" and do not stipulate that they be used at Kroger only, however, there is a small Kroger logo on the bottom. Can these be used at any store, or just Kroger? TIA!!