Can an Old Catalytic Converter Be Cleaned?

Dear Car Talk

Dear Car Talk | Dec 10, 2015

Dear Car Talk:

I'm fairly sure the answer is "no," but is there any way to clean a catalytic converter once it's removed from the vehicle? That's all, folks.

-- Norm

Why? You want to use it as a vase on your dining-room table, Norm?

I suspect you're wondering if you can clean it and reuse it in your car. And the answer to that is, no you can't.

There are companies that will remove the catalyst and reuse whatever is left of the chemicals to create a new or rebuilt converter. The chemical catalysts themselves, which are rare metals like platinum and palladium, never wear out.

When the converter is built, those chemicals are applied to the outside of a ceramic honeycomb that fills the converter. Then, when harmful exhaust gases (carbon monoxide, nitrous oxides and unburned hydrocarbons) pass through the converter, they come into contact with the catalysts and are converted into less-dangerous chemicals that can go out the tailpipe.

Over time, that honeycomb disintegrates, and pieces of it actually break off and get blown into your muffler and out through the exhaust pipe. But it's possible for companies with the right equipment to harvest what's left of those chemicals and reuse them to manufacture a new honeycomb. And it's worth it, because those metals are expensive and represent a huge percentage of the cost of the converter.

But that's not something you can do yourself, Norm. So go apologize now to your wife for running your old converter through the dishwasher.


Get the Car Talk Newsletter