Hello…….. I introduce myself first, so my name is Stefanie, I am 30 years old and drive a white Kawasaki GPZ 600 R, built in 1987!! Now the tank was rusty from the inside with my Kawa, which I affectionately call Diva. Now what do??? I heard from a friend, take DanKlorix, let it work for a few hours and shake it again and again. So I tipped 2 bottles a 1.5 liters into the tank, shaken, maintained, shaken, waited etc. then the Zeuchs so after 2.5 hours ra The rust is still there!!!! Think, think, think!! What to do??? I then bought 3 bottles (as an experienced housewife) Bref Power Cleaner. Bref is really a super Zeuchs, let it work only briefly on soap residues or lime stains, rinse off FERTIG!!!!! It is a red bottle with a white spray head, now stands on the label against lime, rust, dirt, soap residue. And you should not let it work for more than 5 minutes. So I am full of action 3 Flasc hen a 0,75 liters in the tank tipped, let it work about 1.5 – 2 hours and shake again and again in between, then Bref out, rinse properly with water afterwards and see there, the tank looks from inside like NEW!!!! Lightning blank, no rust anymore!!!!!!! So against rust I can only recommend you Bref Power Cleaner !!!!!!!!!!!! Many dear greetings and always a safe ride wish the Diva and Stefanie