A lot of times, especially when I'm having to sing that popular stuff ina tenor register, my throat gets rather scratchy and raw, so that by the end of the set I can't even sing my own material anymore. A vocalist I know recommended to me getting some peppermint essential oil and mxing it with tea.
Instead, I just poured some hot water from the faucet over about five drops of the peppermint oil. Worked like a charm! All the throat gunk cleared INSTANTLY, and suddenly I had my lower register back again. I think I'll have that little bottle with me fomr now on at gigs... a baritone can only handle so much Skynrd.
Just wanted to share :)