Using hot soapy water works best for cleaning it from both your drain and your skin. Prolonged skin exposure to mineral spirits will lead to irritation, but once washed off...
It's extremely hard to end friendships gracefully—there are so many emotions involved. If something terrible has happened that warrants you having to end the relationship, you can quietly slip out...
Some mechanic shops have safe containers for disposing of gas and oil. Autozone stores (among others) offer free disposal of fuels and oil. Avoid pouring them into the general environment.
