Historically, I used a cheap (i.e. $11.00 USD) Type K thermocouple with cloth braid on my Heatermeter temperature controller rig, until my daughter tripped over the thermocouple while she was running around and rendered it unreliable. When I threw the old thermocouple away, it was heavily coated in old smoke and grease due to the environment in my charcoal-fired BBQ smoker.
I invested a bit more in the replacement thermocouple (a Thermoworks TW-113-442-GC Type K, with an armored-metal cable jacket). My question is what (if anything) I should do to prolong the useful life of this thermocouple; can I soak the junction end in apple-cider vinegar to clean it? How can I clean the grease, without damaging the electrical functionality?
Google searches for cleaning Type K Thermocouples haven't been terribly productive.
To be explicit, I am not using a Thermapen; Thermoworks has a FAQ that addresses cleaning this Thermapen, but they do not have anything addressing a simple Type K thermocouple.
Best Answer
It is clear from the picture that the actual thermo junction is contained in a metal sheath. If you saw the actual junction, it would look like two thin wires welded together where they meet. As such, you can aggressively clean (but perhaps not submerge) the probe tip with any means that does not harm the metal jacket. I would probably choose steel wool to give it a quick buffing up.
On the other hand, in a grill application, it would take a tremendous buildup of byproducts before having any real effect on the application. The normal buildup will slightly slow the thermal response (seconds) but it will not cause an overall temperature error.