The easiest proven way to clean rusty bolts

If you’ve ever taken a deep dive under the hood, squeezed underneath the chassis or simply changed a tire you’ve probably learned this important, eternal truth: rust never sleeps.

Rust is most apparent on the engine, particularly the bolts. If left unaddressed, a rusty bolt could corrode to a point where it fuses to the engine block. That’s when things break, and the repairs could be costly.

What’s the best way to remove a rusty bolt?

The “best” method depends on the level of corrosion, but some proven methods of removing a rusty bolt in one piece are:

Impact
Hammering the head of the engine bolt can help shake loose the corrosive bonds. Try a few solid hits then attempt to twist it off with a wrench. An impact wrench can also have the same affect.

Heat
This is basic chemistry; metal expands when it heats up. Heating a bolt head with a blow torch until it is red hot and then allow it to cool will break the corrosion between the threads.

Rocking
It may seem counter productive, but try repeatedly tightening and loosening the bolt. Driving the bolt in just a little further can break corrosive bonds. This method works best in conjunction with a penetrant like WD40.

What’s the best way to clean a rusty bolt?

The hard part is over once the bolts are removed. They must be cleaned thoroughly before being reinstalled or the rust will get worse.

There are several ways to clean rusty bolts, and each method has its advantages and disadvantages.

Ultrasonic method

Ultrasonic cleaning machines harness the power of sound waves to blast rust, grease and dirt off of bolts. Sound interesting? It actually is! Rusty bolts–or any dirty, corroded part for that matter–are placed in a tank of water. At the bottom of the tank is a line of sound generating transducers that vibrate at the right frequency to produce millions of bubbles. These bubbles form and explode almost simultaneously, which sends a shock wave through the water. Those millions of shock waves per second break off corrosion through a process called cavitation.

Pros

Effortless
All it requires is dropping parts in a machine and pressing a button.

Efficient
It’s fast and lifts away corrosion almost to the microscopic level.

Cons

Expensive
Unless taking apart machinery is part of your daily life, it really doesn’t make a lot of financial sense to own an ultrasonic cleaner.

Risks integrity
There are claims that ultrasonic cleaners damage bolt threads because of the constant jostling from the vibrations. It’s unproven, but encourages caution.

Soaking method

This is another “set it and forget it” method that’s popular with mechanics. It involves soaking rusty bolts and other dirty parts in a chemical bath for hours–or even days–and then scrubbing them clean.

Pros

Efficient
The amount of parts you can clean at once is only limited by the size of the tub.Dump in anything that needs cleaning. Chemicals don’t discriminate.

Preserves integrity
Although the chemicals are harsh, they can’t dissolve metal.

Cons

Returning rust
A common mistake people make is not drying off their hardware thoroughly, which leads to more rust.

Scrubbing
Even though the chemicals do most of the work, there is still a fair amount of physical effort involved.

Slow
Depending on the level of corrosion, rusty bolts may need to soak for days.

Dangerous
Working with powerful chemicals without protective gear or proper ventilation can be devastating.

Inconvenient
Disposing of some chemicals can be a hassle. They can’t be flushed down the drain.

Steel brush method

This method is rather straight forward. Pick up a steel brush and get scrubbing!

Pros

Inexpensive
A steel brush is only $2, max.

Convenient
There’s no prep time.

Effective
Methods that require liquids also require thorough drying to prevent rust from returning. This method brushes rust away and keeps it from spreading from the original point.

Cons

Effort
The amount of physical effort required for this method is considerably more than the others.

Slow
If you have more than a handful of rusty bolts to clean, this method is not ideal.

The fastest, safest method for cleaning rusty bolts

Thread Wizard put a new “spin” on the steel brush method by creating an inexpensive product that takes all the effort out of scrubbing bolts one at a time.

What they’ve essentially done is created a steel brush that cleans rusty bolts as they twist through an opening that matches the size of the bolt. It’s ideal for cleaning bolts on the fly. It even makes cleaning large amounts by hand possible when combined with an impact wrench or drill.