-- I got an email about this on Monday (I didn't do it last year). This year, they're offering $30/hour - I assume this is exempt from Uber's commission(?)
Red Cross is a charity I'm happy to support (I also do a regular plasma donation every fortnight), so after reading your review from last year, I'm going to give it a go.
-- You can self-assess 100% but unless it's a trade/commercial vehicle or you've heavily modified your vehicle for purely commercial use, a claim of 100% business use is unlikely to survive audit scrutiny.
the clear liquid part of blood, in which the blood cells, etc. float;
careful and thorough examination.