Restoring Vintage Radios with the VEVOR Ultrasonic Cleaner

I recently attended a ham fest and picked up a Hallicrafters SX-99 shortwave receiver. This beauty was caked with 70 years' worth of grime, so I knew it was going to need some serious cleaning. That's when I reached out to VEVOR, and they sent me their 10L Ultrasonic Cleaner to try out. In this blog post, I'll take you through the process I used to clean some old radio parts and even a few dirty wrenches, all using this handy piece of equipment.

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Setting Up the Ultrasonic Cleaner

The VEVOR Ultrasonic Cleaner comes in various sizes, but I went with the 10L model, which is perfect for cleaning larger items like radio parts or tools. For the cleaning solution, here's what I used:

• 9 quarts of water
• 2 quarts of distilled vinegar
• 1/4 cup of citric acid
• A couple of drops of dish detergent

I filled the cleaner with the water, then added the vinegar, citric acid, and dish detergent. After mixing it up, I set the temperature to 55°C (131°F) and ran it for a few minutes to dissolve the citric acid and mix everything properly.

Cleaning the Radio Parts

The first items I decided to clean were some old radio components. I had a few variable resistors, a PCB board covered in flux, a dirty screw terminal, a switch full of gunk, and some old knobs that had grime deep in the creases. These are parts that typically require a lot of elbow grease to clean manually, so I was excited to see how well the ultrasonic cleaner would do.

I placed everything in the basket that comes with the cleaner. For smaller items like screws and nuts, VEVOR includes a little mesh ball that you can use to keep them from getting lost. I set the cleaner to run for 15 minutes at 55°C, then waited to see the results.

The Results

When the timer went off, I carefully pulled out the basket, giving it a little shake to help release the excess water. The parts were still hot, but the results were immediately noticeable. Here's a breakdown of how each item fared:

• Variable Resistors & PCB Board: The flux on the PCB board had dissolved, making it much easier to work with. The aluminum parts came out looking shiny and new.
• Knobs: These were especially hard to clean by hand, but the ultrasonic cleaner did a fantastic job. A quick wipe with a rag, and they were spotless. However, it did remove the white indicator line from one knob, but that's an easy fix with a bit of paint.
• Switches & Connectors: The switch had a lot of carbon buildup, but most of it was gone after the cleaning. A quick wipe, and it looked much better. The RCA connectors and screw terminals came out looking almost brand new.
• Rusty Screws & Washers: The screws were rust-free, and the washers, which were heavily rusted, were now shiny and clean. I was impressed by how well the solution tackled the rust.

One tip: Make sure you thoroughly dry all parts after cleaning to prevent any flash rusting or moisture damage.

Bonus Round: Cleaning Dirty Wrenches

After seeing how well the ultrasonic cleaner handled the radio parts, I decided to throw in a few dirty, rusty wrenches. I set the cleaner to run for another 10 minutes. When I pulled the wrenches out, most of them looked almost brand new. Even the one wrench covered in some kind of gunk saw significant improvement. I had to scrape off some of the residue, but it was much easier to clean than before.

The rustiest wrench still had some spots of rust on it, but nothing a good overnight soak in vinegar wouldn’t fix.

Frequently Asked Questions

What cleaning solution should I use in an ultrasonic cleaner for vintage radio parts?

A solid all-purpose recipe is roughly 9 quarts of water, 2 quarts of distilled vinegar, 1/4 cup of citric acid, and a couple of drops of dish detergent. The vinegar and citric acid handle oxidation and rust, while the small amount of detergent helps lift grease and grime from radio parts.

What temperature and time settings work best for cleaning radio parts?

Around 55°C (131°F) for 15 minutes is a good starting point for most vintage radio components. The warm bath helps the citric acid dissolve and lets the cleaning solution work into tight crevices on knobs, switches, and PCBs without going hot enough to damage delicate parts.

Is it safe to ultrasonically clean PCBs and electronic components?

Most through-hole boards from the vintage radio era hold up well in an ultrasonic cleaner, especially with a mild vinegar-and-citric-acid bath. Avoid running boards with paper-based labels, sealed relays, large electrolytic caps, or anything with a microphone capsule. Always dry boards thoroughly before powering them up.

Will the ultrasonic cleaner damage painted indicator marks on knobs?

Possibly. The cleaning solution can lift the painted white indicator line off some vintage knobs. The fix is easy with a small dab of paint after cleaning, but if you have very rare or original knobs you should test on a less critical knob first.

How do I prevent rust after ultrasonic cleaning?

Dry every part thoroughly as soon as you pull it out of the cleaner. Compressed air or a heat gun on a low setting works well, especially in screw threads and around switch contacts. A light coat of oil or contact cleaner on bare steel keeps flash rust from forming overnight.

Is the VEVOR 10L Ultrasonic Cleaner worth it for radio restoration?

If you regularly clean vintage radio parts or hand tools, yes. The 10L size handles big knob sets, PCBs, and chassis hardware in one batch and saves hours of manual scrubbing. For a one-time small project a smaller bench cleaner may be more appropriate, but for ongoing restoration work the 10L is a strong fit.