I had a 2KG margarine tub full of brass thrup'ny bits and old pennies that i sent to the recycling about 10 years ago lol It was really heavy, I regret sending it really, it had been my late father-in-laws and for some reason it ended up at ours
The silver 3d bit was still in occasional use in my youth. (They were often used to put in Christmas puddings!). They were replaced in 1942 by the nickle/brass 12-sided thrupenny bit.