All the pictures are showing this chain to be fake. but you say it's solid silver?

Honestly its a half inch. .999 silver or .925 will still melt ice because of silvers thermal conductivity. if you put an ice cube in a tray over the necklace at room temperature and it doesn't melt its FAKE. There are many Easy tests to determine whether you were ripped off. As a jeweler. if you have a good sense of smell the 7.5% copper wont give off an odor. because gold and silver fun fact are odorless. Also the ice test is still used as a tool to determine silver content. as if its plated with silver it wont melt the ice. If the ice doesnt melt its fake. look up the test. some sellers like to save themselves money by saying its solid sterling silver. when its either plated silver or something else thats false advertisement. amazon's the one who will have to deal with sellers and the returns. if i buy this and i use my acid testers on it. and i find out its fake. I would have the seller pulled from amazons sales lists.

How do I keep this change shiny and clean?

I have had it over a year. Regular jewelry cleaner works excellent. It's real Silver, mine has never tarnished black or turned green. I love and people always compliment it. I clean once a month.

I just bought a 24 inch. Is this real Sterling silver?

Yes. Depending on the alloy, because it is real sterling, get ready to have to polish it. (Get the damp jewelry wipes for sale here on Amazon, Walmart or Ace hardware.) For $10 more, rhodium protects the silver and keeps it from tarnishing for a while. Real silver is work.