Whether you're selling platinum coins, jewelry, or bars, it's critical to find a good buyer. There are a ton of businesses that trade in platinum, and they're definitely not all created equally.
Frequently the value of a platinum item is at least partially subjective, with things like rarity, craftsmanship, and other factors heavily influencing the value. It's important to go into any potential selling situation well informed to help you get the best price!
Whether you decide to go with a national service where your items are mailed in and appraised, or a dealer local to Vienna, research is key. Know who you're dealing with by checking with organizaions like the BBB, and know the value of your items by checking spot prices and getting competing offers.
Selling platinum can be intimidating at first for a new-comer, but it doesn't have to be! As with all things in life, preperation is the key to success.
As a general rule, you should look at buying legal tender platinum coins wherever possible. This will almost certainly include less overhead and premium than other formats, and be closer to the true spot price of platinum.
Purchasing rare platinum coins should be avoided unless you really know what you're doing. Some subjective measures of value are easy to misjudge, and may result in you getting taken advantage of.
Governments around the world have seized noble metals from time to time, so keeping your entire stash locally could be a bad idea depending on where you live.
Safe jurisdictions like Switzerland should be considered when you get to the point of holding a significant (tens of thousands of dollars worth generally) amount.
It's important to comply with the law when it comes to buying platinum, and knowing what they are goes a long way.
Under a certain dollar amount, there's no need to declare (which may be attractive to some), but once you hit a threshold you will need to (and should) declare your holdings.
Physical precious metals like platinum are a hedge to the traditional banking system. In a crisis, if the system collapses, it may very well take your property down with it (if it can).
If there is a run on the banks, having your platinum under your direct control means they can't confiscate it, block access to it, or have loaned it out in a leveraged fashion.