Your clan members may donate in those chests from Maymay's blog

Your clan OSRS Items members may donate in those chests. The best part is you could use them to your guilds needs. For instance, you have to pay your slave his salary, but don't have sufficient cash. You check the contribution chest and if there's enough money you cover the servant.

When you put the money inside it becomes a Guild Coin. One Guild Coin is the same as one normal Gold Piece. You may only use the currency for the guilds needs. That's why when you donate you can make sure the owner won't invest the money on something else such as armor, food or anything that he can use for himself. All your cash will be only able to help the guild. Here's what can you do with your Guild Rewards:

Pay/Buy Servant - If you have sufficient Guild Coins you can pay your winner for his services or purchase one from Ardounge.

Buy stuff - You can purchase materials (planks, nails, gold leaves etc.) for your guild with the coins. But just from NPC stores. Guild Coins are untradable so you can't trade them to any player and you can not buy the materials. By way of instance, Teak Plank ( c ). These substances with ( c ) after their name are untradable and can only be utilised on your guild. So you can't rely on them in your typical POH. You can get Gnome Glueworms by learning the hunting technique from the gnome King Narnode for 1,000gp. You require level 35 Hunting to capture them and you can grab them at the Tree Gnome Stronghold swamp with no tools. If you do not have the required Crafting level then deliver the Buy OSRS Accounts materials to Master Crafter from the crafting guild. He will craft it for you for a charge.