The singers were a bit 'rusty' after the long break.
My tennis skills are a little 'rusty'.
a 'rusty' old car
(..) before he lets the Germans drink it. This ought to take the sting out of being occupied. You said it. Here's looking at you, kid. My German's a little rusty. It's the Gestapo. They say they expect to be in Paris tomorrow. They're telling us how to act when they come marching in. (..)1942 Casablanca
(..) For old time's sake. I don't know what you mean, Miss llsa. Play it, Sam. Play "As Time Goes By. " I can't remember it. I'm a little rusty on it. I'll hum it for you. Sing it, Sam. You must remember this... A kiss is just a kiss... A sigh is just a sigh... (..)1942 Casablanca