I'm afraid you have overlooked reading my thread
Luckily, it has been noticed by other forum members almost 12,000 times!
Fernando (Nando) obviously did, so his guess was the closest!
You will find out that your item in question is anything but scrap: it is a German 'military' caliverman's flask of about 1590-1612, a relatively short span of time in the Late Renaissance period which allows assigning a very exact date of ca. 1600
to your flask.
It is preserved in very good and original condition, complete with its long frog hook
(which actually is not a 'belt' hook!), mounted on the reverse of the flattened natural cowhorn body, and all the iron mounts obviously retaining much of their original dark bluing.
Please do not 'clean' the iron mounts
, they originally never were 'shiny bright'!
I strongly recommend taking a cloth, putting a bit of olive oil (that was the only oil used as a means of rust prevention 400 years ago!) on it, and wiping all the iron surfaces.
Just let the oil get dry for a few days, without handling the flask, and you will have achieved a perfect state of conservation.
There is one thing about 400+ year-old flasks that has always been of important historic interest to me: were they really used, meaning: are there traces of black powder in the bodies of these flasks?
Thus, it would really be great if you could find a perfectly fitting screwdriver to carefully remove the upper of the two transversal screws fixing the cowhorn and the iron top mount, and have a look at the flask's 'bowels'! Please gently rub your finger against the inner walls of the cowhorn; if the finger comes out black, you will know - and please do post the photos of both the innermost of the flask's body and your finger!
Of course, I have done that with nearly all the about 30 'military' flasks in my collection that are ca. 350 to nearly 500 year-old, as well as with hundreds of similiar samples in both museums and private collections, and for more than 35 years of my research studies.
The outcome was that about 70-80 per cent of all those 'military' flasks showed no traces of black powder whatsoever - so they actually never 'saw service'!
They obviously were ordered by the armories in such large numbers that most of them have never been used - a fact which, at the same time, accounts for their usually good state of preservation after such a long time!
I attached a few photos of my highly specified collection of earliest German and Austrian 'military' long guns and all sorts of accouterments, from ca. 1360 to 1700!
You may also be interested to learn more about other types of 400-500 year old 'military' flasks; so please read my threads, especially