Just soaked it upside down (biggest cog up) for 15mins in a container big enough to accommodate the cassette. In fairness this cassette has only seen indoor trainer miles but this is next to brand new
Anyway - I’ve rinsed it with water and some Dawn and can still smell the MS. Anyway to know I’ve rinsed it enough? Or what are the signs I need to rinse it more?
What is the concern and/or reason for rinsing? Mineral spirits will evaporate off fairly quick. I typically use pressurized air to speed up the process but would not rinse with soap/water. Mineral spirits does not have any corrosive interactions with metal, but water obviously does. And some soaps make it worse.
Generally, there’s no need to rinse off OMS. It’s like a very thin lightweight oil and it will all evaporate in a few days anyway. If I want to hurry the process for some reason, I’ll blow it off with compressed air.
Yeah, I’d just clean with MS and you should be ready to go. Even if it was still wet with MS when you put the chain on, it’s not going to dilute the chain lube in any measurable way.