The Cartoon Quote Game...

Pardon me, Monday got ... weird. So we're doing good advice, eh? Okay, I can do that.

"Keep your pencil in your pocket."

May we have a hint please?

....

Actually, now that I review this one, it's actually a dud. A live actor spoke it, though he'd become animated later in the film. Instead, let me substitute this gem:

"Oh, thank you so much. It was very confining in there."
"You're very welcome. But why did you have to be in the last can?"
"But I wasn't; I was in the first can. You started from the wrong end."

Ah, I know this one. It's Mac and Tosh from, I Gopher You.

Precisely, these are the Looney Tunes' politeness pair, the Goofy Gophers Mac and Tosh. One gopher stumbles into a canning machine, and the other has to rescue him with a handheld can opener. Well done, Saltyboot.

Thanks! Sorry it took so long, but I found one.

"When he stays out all night, he's always grumpy the next morning."

"Then he must stay out every night."

Found it. It's Merlin and Arthur, AKA Wart, from "The Sword In The Stone."

Yes, they were talking about Archimedes the owl.

Thanks, Salty. Now for a real good one:

"When he strikes this note, instead of a xylophone, he'll be playing a harp."

Daffy Duck placing dynamite under Bug's xylophone from Showbiz Bugs.
Always be wary of playing "Those Endearing Young Charms" on any musical instrument.

Good job, Glowworm. . That's it, 100 %. You may go again.

While we're on this subject...
"Old gag, new twist."

Hint: Much like the previous quote, the character is also given a chance to play "Those Endearing Young Charms" on a xylophone. However, she's well versed in such a gag and something quite different actually happens when she strikes the instrument.

Intriguing hint, GW. From the cattiness of it, I'm going to lob a brick and say it's Babs Bunny from Tiny Toon Adventures, subverting this classic Looney Tunes gag, most likely to Buster Bunny's detriment.

Nope, not Babs Bunny, but you are getting warmer. This is from a 90's cartoon series produced by Steven Spielberg--but it's not Tiny Toons. No, this character has a bit of a drier, more sarcastic bite to her wit--and she's not afraid to hurt people.

It's Slappy from Animaniacs. From Slappy Goes Walnuts.

Correct. This is the gag in question. Basically, Doug, the squirrel-hating dog sets up a trap for Slappy in the form of the old dynamite rigged xylophone-complete with sheet music for "Those Endearing Young Charms" as an "apology" present. This gag is so well known, even her nephew begs her not to play the song. She does--and on the part where the character usually doesn't play the rigged notes properly--Doug the dog blows up. This is Slappy's explanation of it.

Lets stick with the theme shall we?

"Well at least up here, I don't have to worry about no booby traps."

Hint: This is said right after the "Those Enduring Young Charms" gag.

Found it. It's Private Snafu, from, what else, "Booby Traps."