What I used for cleaning the rubber spin of the device was rubbing Alcohol but materials may very to ones liking of how that product works than others. but here are what I recommend for cleaning the rubber spine:
How to Clean Rubber Products

Let the wet rubber surface air-dry.

Wipe the rubber object with a soft cloth to dislodge loose soil.

Squirt two drops of liquid dish soap into a container containing a cup of warm water. ...

Immerse a soft sponge in the sudsy water. ...

Rinse the sponge with clean water. ...

Let the wet rubber object air-dry.

Ultimate Ears is a great brand but having to try to clean their speakers are irritating. Hope you have luck on your end and tell me what works better in the comments below. I will try them out myself. If you like the vid give it a thumbs up of you didn't thumbs down. Please like and Subscribe and see you in the next one :)