dack - Dutch
Dutch is alsjeblieft (informal), alstublieft (formal), thanks (informal), dankjewel (informal), or dankuwel (formal). The former probably means "as you desired" in old Dutch, the latter "thank you well", and the formal/informal variants simply insert the right word for "you" (je or u). And then there's thanks being commonly used. Or also bedankt, sounds kinda formal to me as well, not sure when you'd use that instead of dankuwel
Just "dank" (maybe you wrote that and autocorrupt kicked in?) is not really a thing we say, it just means "thank" which you'd also not say by itself in English (unless you're Rocky)
Edit: writing "dank" in an English sentence feels like everyone will think our thank-yous are like dank memes. The pronunciation of the "a" there is as in Clark; the English pronunciation of dank would map to denk in Dutch and means think!
Where does all that stuff go after it's used? I can't imagine it's all recycled properly (let alone reused) but also not really that the bulk is not separated out at such volumes