WD40 is a mixture of fish oil and kerosene together with some other chemicals and its usage in the tank is not preferable because it mixes with petrol.
You can use 3M petrol addictive but I am doubtful about its ability to prevent rusting of the tank because the rusting part is not in contact with petrol.
Burdahl, Iftex, Thermol etc are some of the other additives claiming the same quality of 3M. And this kind of additives is added in branded petrol like Xtra premium, Speed, Power etc.


Very informative I should say.
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