If you only consume occasionally pretty much all of those substances are only testable 1-3 days after consuming them, if you're a regular user it's usually between 5-7 days maximum.

As a regular user Ketamine could be tested up to 14 days in your urine. THC has the longest timeframe with up to 60 days when you use regularly.

Will share what I know, but for the record I'm a layman - any toxicologists in the house?

Depends on the compound, dosage, frequency of use, sample type, and test method. A screening immunoassay, for instance, will usually have a higher cut off than an LC-MS/MS (liquid chromatography tandem mass spectrometry) test. Good rule of thumb for your typical urine drug of abuse screen is 2 to 3 days, but again this varies (THC, for instance, can be detected for a loong time depending how big a stoner you are/how long you've used).

The stuff folks are mostly worried about re: Elon? About 2-3 days, assuming the typical urine DoA screen.

Now, you can also test other sample types (hair, nails, etc.), and in which case some compounds are detectable for much longer (90 days, etc.). But that window is also impacted by stuff like (in the case of hair, for example) how much hair is collected, where it's collected (scalp v. body hair), how long after last use it's collected, etc.

Even the ones on his balls?

(Sort of kidding, though fr I'd prefer a body hair collection anyway)