Assuming that the coins are in reasonably good condition, and that they are general circulation coins rather than "Proof" or "error" coins, it would go something like this, in no particular order -
Halfpenny - 1923, 1915, 1918 and 1939.
Penny - 1920 (no dots), 1930, 1925 and 1946.
Threepence - 1915, 1912, 1914, 1923 and 1942M.
Sixpence - 1918, 1922, 1924, 1939, 1952 and 1953.
Shilling - 1915, 1915H, 1921*, 1933, 1911, 1912, 1914, 1924, 1939 and 1940.
Florin - 1914H, 1915, 1932, 1911, 1912, 1913, 1915H, 1919M and 1933.
As a general "rule of thumb", most, if not all predecimal British coins would have some value beyond face value, if only for the metal they are made from. As another general "rule of thumb", most British decimal coins will have only face value other than for "uncirculated" or "Proof" coins and the very occasional error coin such as the undated 20 Pence coin and the 1983 2 New Pence coin.
Australian predecimal Proof coins were not always packaged as they are today and may have only been wrapped in tissue paper, cellophane or similar. Even the best protected and cared for coins will show some discolouration. Medium to dark brown and black are not good colours. Bronze coins such as the Australian Penny that have been properly stored and protected and not handled, should still show most of the original mint lustre with only minor discolouration however, the older the coin, the greater the possibility for discolouration. This may be due to oxidisation if nothing else. Because of the relatively high value of Australian predecimal Proof coins, potential purchasers will be a lot more critical of any perceived deterioration of the coins. Pre Elizabeth II Proof coins were only struck in very small quantities of possibly less than 20 each year, if at all. Should you have any nagging concerns with your Proof coins, take them along to a reputable coin dealer who should be able to advise and give a valuation.
The copper content of 20th century British predecimal Pennies, Halfpennies and Farthings varied from 95.5 to 97%. When the use of silver in coins was discontinued after 1946, all British "silver" coins were made from a copper-nickel alloy consisting most commonly of 75% and 25% nickel.
Australian people value education and family the most
If your Australian 50 cent coins have been circulated, probably not much more than face value, since coins from most years are still in circulation. Individual coins have a value determined by the past year or two of buying and selling coins between dealers and collectors. Not all years of Australian 50 cent coins had "Proof" coins minted. A "complete" set of mint "uncirculated" coins could be valuable, but don't make plans for retirement. I recommend that you take your collection along to a reputable coin dealer will be able to give you an accurate valuation.
There are many places online that one can buy Australian coins as well as many local stores that one can visit. One of the most popular places that one can buy Australian coins is the Australian website perthmint.
There have only ever been four Mints in Australia, the Melbourne, Perth, Sydney and Canberra Mints. The Royal Australian Mint Sydney, was opened as a branch of the Royal Mint London in 1855 and closed in 1926 with all minting responsibilities being dispersed to Melbourne and Perth. During its period of operation, the mintmark was "S" on British coins. On Australian predecimal coins, there was either no mintmark at all, or a complicated placement of dots on Pennies and Halfpennies. The Royal Australian Mint Melbourne, was opened as a branch of the Royal Mint London in 1872 and closed in 1967 after the introduction of decimal currency with all minting being taken over by the newly opened RAM Canberra. During its period of operation, the mintmark was "M" on British coins. On Australian coins, there was either no mintmark at all, or a complicated placement of dots on Pennies and Halfpennies, or an "M" on all other predecimal coins. The Royal Australian Mint Perth, was opened as a branch of the Royal Mint London in 1899 and is still operating. It is currently owned by the Western Australian Government and is responsible for producing most of Australia's bullion. During its period of operation, the mintmark was "P" on British coins. On Australian predecimal Penny and Halfpenny coins, there was a dot "." placed variously after the "Y" in PENNY (PENNY.) or after the "A" in AUSTRALIA (AUSTRALIA.) or between the "KG" (designers initials) (K.G). All silver coins were minted at the Melbourne Mint. The Royal Australian Mint Canberra, was opened in 1965 and is still operating. Since 1982, it produces all of Australia's circulating coins and mints coins for many other countries. Since it is the only mint producing Australia's circulating coinage, there are no mintmarks used since 1981. Australian predecimal coins have occasionally been minted overseas at London (L) or (PL), Heaton Birmingham (H), San Francisco (S), Denver (D), Bombay and Calcutta (I). I am not even going to attempt to explain mintmarks on Australian decimal coins. Where mintmarks are used, these mostly include blunted first or second whiskers on the 1 cent coins, blunted claws on the 2 cent coin, blunted spines on the 5 cent coin, etc. If you have a great need to know the details, get hold of a "Pocket Guide to Australian Coins and Banknotes" by Greg McDonald. It is a relatively inexpensive and detailed wealth of information.
All Australian coins feature the reigning Monarch on the obverse, currently Queen Elizabeth II since 1953. For the introduction of the Australian decimal currency in 1966, it was decided to have a uniquely Australian design for coins and most banknotes. See the links below to the Royal Australian Mint (RAM) and The Reserve Bank of Australia (RBA) for images of current Australian coins and banknotes.
Most airports will not exchange coins other than coins in their own currency, so if you want 100 Australian dollars in Pearson (Canada) they will usually give you the Canadian amount (with Canadian Coins), if you want 100 Canadian dollars changed, they will give you the balance in Canadian coins. Donate the Australian coins to charity.
There are four different portraits of Queen Elizabeth II on Australian coins, three of them on Australian decimal coins. The 1984 coins were the last year the second portrait was used. These are the One Dollar coins that were minted for general circulation. Standard non-commemorative One Dollar coins - 1984 - QEII second portrait and 5 kangaroos 1985 to 1998 - QEII third portrait and 5 kangaroos 2000 to present - QEII fourth portrait and 5 kangaroos Commemoratives - 1986 - QEII and International Year of Peace 1988 - QEII and Australia's Bicentenary 1993 - QEII and Landcare 1996 - QEII and Henry Parkes 1997 - QEII and Charles Kingsford Smith 1999 - QEII and International Year of Older Persons 2001 - QEII and Centenary of Federation 2001 - QEII and International Year of the Volunteer 2002 - QEII and Year of the Outback 2003 - QEII and Australia's Volunteers 2003 - QEII and Women's Suffrage 2005 - QEII and 60th Anniversary of end of WW2 2007 - QEII and APEC 2008 - QEII and Centenary of Scouting in Australia 2009 - QEII and 100th year of the age pension 2010 - QEII and Centenary of Girl Guiding in Australia There are many other One Dollar coins that were minted as non-circulating legal tender (NCLT), not for general circulation.
Most likely no. Most British predecimal coins are no longer legal tender. The predecimal Crown was never demonetised and is still legal tender. The decimal Halfpenny, the larger pre-1990 5 Pence, the larger pre-1991 10 Pence and the larger pre-1997 50 Pence have all been demonetised and are no longer legal tender. The Commemorative 25 Pence and Five Pound (Crown) coins are legal tender, but not intended to be circulated. All other British decimal coins should be all right to spend.
Mint marks are - I = India (Calcutta or Bombay) PL = Royal Mint London K.G = Perth Mint (the dot only) KG is the designers initials M = Melbourne D = Denver S = San Francisco H = Ralph Heaton, Birmingham . = Perth Mint Most predecimal coins without a Mint Mark, were minted at the Melbourne Mint.