We use these brushes for cleaning on a daily basis. The NYLON head brush can be used for general cleaning on finished surfaces like bare aluminum or to clean crap out of gear teeth without harming them. The BRASS head brush can be used for brushing side plates to remove old bait stuck to them, and also to clean a bit more aggressively internally. The STAINLESS STEEL head brush should only be used in areas where small scratches will not be noticed. We use this one on steel gears to clean the teeth or to remove salt deposits. Always test a small area when using the metal head brushes before you go all out with them....some paint finishes are more succeptible to scratching than others. You will find these tools indispensible in everyday cleaning!!!