Ebay or gemm are your best sources for determining value, however condition is also a determinant of value and that will be hard for you to gauge without playing the records.
Unfortunately, most records, old or otherwise, have very nominal value. You might just check your list against ebay and drop those of little value off at Goodwill and take the write-off.
Unfortunately, most records, old or otherwise, have very nominal value. You might just check your list against ebay and drop those of little value off at Goodwill and take the write-off.