This is a difficult product to review. I've used another brand of sealant and had some flats as the sealant wouldn't seal the puncture even though it was very small. Since I've used the Muc-Off sealant I haven't had a flat so I guess either it's working or I've just been lucky to avoid any debris that would cause a puncture. I haven't seen any of the purple liquid on the outside of any of the tires. I'm not a fan of the pouch as it's difficult to add a specific measured amount.