The scrap price of a silver half depends on the current spot price of silver. As of 10/20/2009 scrap buyers are paying around 10x face value for pre-1965 90% silver US Coins.
That said, taking the coins to a scrap buyer is probably the worst way to make a profit from them. You should certainly be able to sell any common date, decent-quality coins made since the 1940s for more than their silver value, and anything that's rarer would of course bring even more.
As a worst-case example, one of my relatives sold a set of Mercury dimes for their metal value at a time when they were worth only slightly more than face value. He made a 10 or 15% profit on the metal, but lost hundreds if not thousands of dollars because he didn't have them appraised for their collectors' value.
There were no silver dollars issued by the US Mint in 1964.
1964, 90% silver: around $8 1965~1969, 40% silver: around $5 The prices are if the coin is in superior condition. If worse, worth less
It is 90% silver and worth a bit more than $10 at current silver prices.
90% silver, 10% copper. It's worth about 1.25 at today's silver prices. Dimes, quarters, halves, and dollars dated 1964 and earlier all are made from the same alloy.
1964 half dollars are 90% silver, currently worth just under $9. Then halves dated 1965-1970 are 40% silver, worth about $3.50 (as of 6 May 2013).
1964 is a common date, but it's 90% silver. At present, a '64 half is worth a little over $10.
1964 was the last year for silver quarters. At current market prices, one is worth about $5.
For circulated half-dollars, ones dated 1964 are 90% silver and worth about $15.50 in silver value. Half-dollars dated 1965-1970 are 40% silver and worth about $6 in silver value. Circulated examples of 1971 and later half dollars are only worth 50 cents. Coins in mint sets that are uncirculated or proof may bring a premium to collectors but in general there is low collector demand for Kennedy half dollars outside of their bullion value.
1964 is an extremely common date for half dollars. At present, they're worth around $11 for their silver content.
1964 is an extremely common date for US half dollars. As of August 2017, one is worth $6-and-change for the silver.
Yes, the reason why quarters (and dimes, and half dollars) dated 1964 and earlier are worth more than their 1965 and later coins is because they are 90% silver.
Yes, all dimes, quarters, half dollars, and silver dollars 1964 and older are 90% silver.