How about Clan Castle Depot for donations, let me explain...
How many times has someone asked for a troop only to have that donation request fulfilled by another member leaving you with an unwanted pekka, balloon, or golem? Sure you then use it on your next farming raid only to have that item be requested 10 minutes later leaving you with the annoying decision to recook another troop or not. Or how many times have you waited an hour to unload your dragon for donation so that you can finally attack in war, only to finally give up and trash the dragon into the ethernet netherworld. As a passionate COCer, it feels so wasteful. The solution, instead of junking these troops, dump them in to the Clan Castle Depot.
May I suggest that for each clan you can have a common clan castle depot for common storage and common retrieval of troops? Perhaps make the depot capacity 200. And then each player can draw from that collective CC depot every hour or two. Create some sort of tracking record as to show who is filling it up and who is checking out the troops or just include it in the existing donation status. And perhaps you divide the depot for war troops and regular troops. I'm maxed out(except for walls) and I love donating troops to the rest of my clan. My clan's reward for helping me max out should be the ability to have access to my clan troops, but why must I sit on the chat constantly with troops queued up so that my donations won't be usurped by another clan member who is also eager to donate?