You'll need a hose, bike cleaner (like Simple Green), a tooth brush or cassette cleaning brush, chain cleaning tool, and rags/cloth to wipe down the bike. Then you'll need chain lube and lube for other moving parts (like brakes, derailleurs, etc. You should re-lube the cables and inside of cable housings. Don't use lots of pressure and don't spray water into any holes in the frame.
Clean anything else that appears to need cleaning (like rims, hubs, inside of fork, etc).
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.