The idea of gifting or trading opens up a whole can of worms.
If you had personally been on the forum a long time, and, or ,conducted a search before you posted, you might know that this is not a new suggestion.
An idea which, as there has/had been a gift function button a very long time, must have been considered for inclusion but for good reason,subsequently not introduced.
If you had been playing a very long time, or spending lots of real cash , then you might genuinely have excess materials, otherwise its quite unlikely, as there isnt really such a thing as excess materials, as they are always introducing need into the game.
If players want to specialise,its quite simple enough to avoid attacking invaders you dont need, and leaving them for your clan members that do.
I cannot imagine that anyone in your clan has any need to trade the common materials as they are just as likely to have what you call unused material as anyone else.
The basic idea has been somewhat altered, but essentially you are not supposed to have everything you want straight away,but take time in getting them, if not the game could give you everything from the start, and to what advantage for anyone?