Cedar and other woods give off toxic fumes that discolor coins. If you put them in a safety deposit box, store each coin in a separate paper envelope. A coin shouldn't be rattling around with other coins because their edges might cause nicks. Temperature does not really matter, but it's a good idea to store the coins when it is not humid to avoid trapping moisture. Thai Rama IV 2-baht, undated.
Some countries issue special coins to commemorate a special event.
Some of the modern ones appreciate in value, but it is often difficult to sell modern issues for a quick profit. You shouldn't think of them as a short-term investment. They're more for collecting. A complete series makes an auction more attractive. But the auctioneer would not sell it as one lot because collectors already have their own pieces and are looking for missing items.