It's known as Numismatics.
Curency collecting is the field of Notaphily which refers specifically to the collecting of "bank notes" or currency as we call it. Sometimes collectors in this field are also called "rag pickers" particularly if they are collecting low grade currency, grading refering to the condition of preservation of the note. Collectors can be called Notaphiles which is not dissimilar to Bibliophiles (the book folks). The overall field which would include things like coins (numismatists), bank notes (Notaphiles), old stocks and bonds (Scripophilia) and stamps (Philately) is usually generally, and incorrectly, referred to as Numismatics. This comes from the Greek "Nomisma". And a bit more to help you interpret the Greek: "Scrip" designates ownership right. "Philo" designates "love of" or "to love". "Ateleia" designates "an exemption from payment". There are many more but that should suffice for the moment.
Generally speaking, no. Older notes are easier to forge and will have been withdrawn from general circulation. Old notes can normally be exchanged by bank branches.
In the East Rand, you can exchange old paper notes at local banks, such as Standard Bank, ABSA, and First National Bank, which typically offer currency exchange services. Additionally, the South African Reserve Bank has branches where you can exchange old notes for new ones. It's advisable to check with the specific bank locations for their policies and hours of operation.
will the NatWest bank change my saved old 20 pound notes if I am one of their customers
You would have to pay them in to a bank (if you still can).
I have 3 old 1945 central reserve bank of china notes of 5000 yuan do they have montary value today
Newspaper Collector
New money or extra amount of bank notes are issued on reasons: GNP & GDP increased, Foreign reserve high; old bank notes are to be replaced (due to damage, destruction, lost), or artificially to produce new bank notes (it will cause devaluation)
You can change old Irish bank notes that are no longer in circulation at the Central Bank of Ireland. Additionally, some commercial banks may accept them, but policies can vary, so it's best to check with your local bank. There may also be opportunities to exchange them at certain currency exchange services, but again, this varies by provider.
Old notes can be exchanged for Euros at any Dutch bank. You could also ask for advice from your own bank.
No, you cannot pay old ten-pound notes into your Lloyds Bank account after the 1st of March 2018, as they are no longer considered legal tender. However, you can still exchange them at the Bank of England or deposit them if your bank allows it, but this may vary by institution. It's always best to check directly with your bank for their specific policies.
i dont know but the song is called your a grand old flag