Use 99% isopropyl alcohol. Add in a teaspoon of table salt -- it won't dissolve in the alcohol and will act as a mild abrasive to help remove stubborn residue. Rinse thoroughly with water afterwards.

If you're really serious about your cleanliness, a desktop ultrasonic cleaner is also amazing for cleaning bowls and downstems. You can get them for a few dozen dollars from Amazon and the like.

Soak in 95% ethanol overnight and then everything comes off with an easy wipe if you can get to it. Definitely safe, but I’m curious if these other solutions dissolve completely without a wipe?

'Orange cleaner' is very effective in this case.

I make it by macerating orange peels in 95% ethanol.

Acetone, after removing all rubber seals, then rinse with alcohol and boiling water.

Isopropyl works well