Thank you all for your help! The sonicator took its time, but it managed to agitate the solids out of the rotor eventually.

The rotor is now clean, but please feel free to share more advice!

Thank you! I left the samples in a sonicator overnight, and it worked wonders!

Thanks for the advice. The sample is coating the inside of the rotor. The caps aren’t stuck.

The photo is just to show a rotor and make the post more catchy to passersby :)

Currently sonicating! But it really doesn’t seem to dissolve in anything.

I’ll try to contact the manufacturer and ask for their advice.