Navel Jelly is phosphoric acid and you can get cheaper versions at Home Depot or Lowes. Phosphoric acid is better rust-remover because it has preferential action against rust and stops when it reaches good metal. The other acidic products used by a lot folks do not stop at good metal and will continue dissolving your bike/part until there's nothing left.
I recently used a gallon of stuff in liquid form from Home Depot for a motorcycle gas-tank that was severely rusted inside. Poured it in, sealed up tank and rotated 30-60 degrees every couple of hours until entire inside had been soaked. Came out nice and clean like fresh metal! Also leaves rust-resistant phosphate coating on surface as well. But best to cover with POR-15 and then primer & paint.
Last edited by DannoXYZ; 01-06-18 at 11:00 PM.