You can either dress your cat (which can be home made from an old jumper) before letting him out but if he gets out it is important that afterwards he is brushed to remove all of the debris that can get caught in the fur. It is also recommended that every 6 weeks(depending on the product ) he is treated against fleas and he must also be treated for worms. If his feet get dirty it is important that they are washed in lukewarm water and dried properly with a dryer. If the cat is going near plants that are treated with insecticide he must also be washed and dried properly. What scares me more is the possibilty that there may be toxic plants which could kill him. That is more important than his coat as the coat can be shaved and will grow again but if he gets poisoned he could get ill. I hope my answer is helpful.