You don’t need nuts and bolts or a chain, simply a distilled white vinegar. Fill the tank, rotate it every day to soak, ensure you get the underside of the top too.
If you want faster results, Toilet bowl cleaner works. But you need to neutralize with baking soda and water after both treatments. A quick slosh of diesel, 2-stroke oil, whatever to prevent flash rusting.
If you throw nuts and bolts and chains in with vinegar, the vinegar will also attack them. What’s the point of that? The approach of tumbling in a dryer is silly, let the chemicals do the work in a passive fashion. Drain the tank. Done.