Uploaded July 2018 | Updated September 2026, 1 week ago

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Acid is explained as the most efficient and best penetrating oil for removing rusty bolts that are stuck and impossible to open.

The use of muriatic acid is shown on a railway bolt nut that has been in the ground for 20 years, and completely rusted together. Muriatic acid is also known as hydrochloric acid.

Only 60 minutes is required to completely remove all rust even down in the threads by immersing the bolt with the stuck nut in the acidic solution.

Muriatic acid or hydrocholoric acid is a common chemical sold in almost every hardware store or paint store, and is also the acid in the human stomach. Some people call it the rust acid.

WD40 and other penetrating fluids (oils) are much inferior and do dissolve rust to an extent they open the threads of rusted bolts.

A solution of acid may be used in many applications where bolts are stuck, enabling more efficient and simple method than soaking in penetrating oil.

Muriatic or hydrocholoric acid is a strong acid and caution needs to be taken to avoid burn wounds or other injuries. Full safety outfit is needed.