I haven't done this yet. But it is recommended to add stablizer into gas tank, and change oil after the season. although I don't see the point to change oil now insdead of do it next spring.
The best is to exhaust it (consume the gas completely). A couple other options are to drain it or to add fuel stabilizer.
For engine oil, it's better to change it now than doing that next summer. I think it's better to let clean oil to stay in the engine than having dirty oil there for half a year.
I haven't done this yet. But it is recommended to add stablizer into gas tank, and change oil after the season. although I don't see the point to change oil now insdead of do it next spring.