It's available online, Amazon for example.

The CRC QD Electronic Cleaner is essentially the same thing, different brand.

Just be sure to follow instructions, remove the batteries, and give it extra time to dry. It's not a permanent fix. I use the stuff on some things and have to reapply it every few months, mostly the shitty volume knob on my Razor keyboard.

Even though parent comment is clear, some people might glance over the WD-40 part: this version is the one you want.

And yeah, +1; it works great. I use it on my joy-cons from time to time.

Use contact cleaner to clean it out; DeoxIT D5 is a classic suggestion, but I use WD-40's offering.

I experiencied some controller drift early on & this corrected it - power off controller (maybe not needed but better safe than sorry) - spray some electronic contact cleaner onto the thumbstick ball & move the thumbstick around to work it in. Shake out the excess & power the controller back on. You'll be gtg after that.

https://smile.amazon.com/WD-40-Specialist-Electrical-Contact-Cleaner/dp/B00AF0OFVU

You don't need to use DeOxit. I like the stuff, but it's also priced for audiophiles. You can just use contact cleaner that you can buy much cheapers at an auto parts store. You can buy CRC for about $10 for a big can. Or you could buy WD-40 branded contact cleaner from Amazon for about $7.

https://www.amazon.com/WD-40-Specialist-Electrical-Contact-Cleaner/dp/B00AF0OFVU