I love to see handsome villains, or arrogant boys humiliated, pied, gunged on tv or movies.
The best scenes tend to have these elements:
-Public humiliation.
-Sticky and / or odorous substances covering their bodies.
An example: Biff Tannen and Buford "Mad Dog" Tannen (Thomas F. Wilson) covered with manure in the trilogy "Back to the Future". Funny scenes.
I think Professor Fate (Jack Lemmon) is one of the most villain more humiliated, gunged; in the film "The Great Race" (1964): cover with cakes, pies, mud, honey (I'm not sure if pig manure too) and falls into a cesspool. Poor Professor Fate.

Which are your fabourite scenes, (movies, tv soap) with handsome villains pied, gunged, etc?

I think you can find here.

https://www.youtube.com/user/ghffh9712/videos

Men at Work with Emilio Estevez and UHF (both horrible movies) have some nice muddy comeuppances for a villain and a villain's spoiled son, respectively.

jjwam - are these the locker scenes or did I miss a much better muddy part?

The modern remake of leave it to beaver has some nice chocolate and pie related consequences for the bullies, also a nice scene in disorganised crime with a farm truck. George of the Jungle has am elephant dung facial for the villain. Sure there are lots more guess would need a look at comedy focused movies that seem to do this trope well

Meant the very last scene in Men at Work when the corrupt industrialist is tormented and sent down the tube into the muddy water in his nice 80's dbl-breasted suit.
https://youtu.be/uVXQWXpXmvc

Ah, bit too watery for me i like the two locker scenes personally though i wish there had been much more brown muck over the guys

I ran through my database of messy movie and TV scenes and ranked the top 5 times when the bad guy really gets his messy comeuppance. I provided clips where I could find them (special thanks to nc1412 on youtube for the fantastic collection)

My Top 5:

1. Suite Life of Zach and Cody (episode: First Day of High School)
School jock/bully (Matt Angel) dizzily dips his face in a dish of blue paint
https://www.youtube.com/watch?v=Z3a2WD4sPj4

2. Step by Step (episode: Walk Like a Man)
Smug asshole (Brandon Call ) gets bowls of guacamole, sour cream and beans shoved into his face at a party
https://www.youtube.com/watch?v=YZFtYgUEC70

3. Cat and the Hat (2003 film)
Pompous evil neighbor (Alec Baldwin) slips out of pipe completely coated in thick purple gunk. Extra sludge from the pipe squirts onto his face as he lays defeated and disgusted.
https://www.youtube.com/watch?v=aOKPVIXZRUc

4. Even Stevens (episode: Scrub Day)
School bully (Ty Hodges) gets a pot of thick chili pour directly on his face.
https://www.youtube.com/watch?v=2P9IPOLzx1Y
Beginning at 21:15

5. Daddy Day Campy (2007 film)
Villain dad (Lochlyn Munro) has a big cream pie thrown directly at his face by a boy on skateboard.
https://www.youtube.com/watch?v=_eipTOHwCdE

Honorable Mention:
Pete's Dragon (1977 film)
Country bumpkin villain (Jeff Conway) gets knocked face-first into a thick, sticky mud pit and emerges completely covered in the grey stuff

An episode of the thundermans, Max's minions, where the nerds turn into pranksters, then get covered in caramel and popcorn.
The movie The Borrowers, the villain gets a cheese shower, and sprayed with foam.
Max keebles big move, the bullies get covered in ice cream, and garbage.
The paper brigade, the bullies get attacked by dogs, covered in food, and pelted by paintballs.
Beverly hills Chihuahua 2, the robbers get covered in pizza dough and flour.

In this web, http://baddieshumiliated.tumblr.com/ you can find a lot of pics, gif, videos with bad guys, villains punished, humiliated, exposed to public humilliations, etc.; and some cakes or pies in the face, gunge scenes.

And:
From "The grate race"
Professor Fate - Daredevil Stunt #1:
https://www.youtube.com/watch?v=1Nkm1vBs2w4
Professor Fate - Daredevil Stunt #2
https://www.youtube.com/watch?v=86ZnWc1B7W4

Dazed and Confused. Ben Affleck is going to paddle someone, when some guys drop some white paint on him.

Bejeweled. Sniveling rich prep who was a big crybaby gets a bunt cake dumped on his head.

B.R.A.T Squad. Kid and his friends expose the bad guy during a JROTC event, or something, and his jerk older brother falls into a cake, which was supposed to be protected at all costs.

Christmas Every Day: Groundhog's Day becomes December 25. During a school play, main character replaces snow with chocolate milk. One day, his rich uncle gets it dumped on him, another, the high school bully does.

Running the Halls: Three guys try to make a business out of sundaes. The hall monitor comes in to inspect their room, and discovers their stash in the ceiling, which has all melted...and falls on the monitor.

Spy Hard: Skinheads cut the brakes to a bus...driven by Ray Charles. Scenes from Speed ensue, while people are performing dentistry and decorating a cake. Agent WD-40 (Dick Steele) stops the bus, lead skinhead falls into cake.

George of the Jungle: Boy likes jungle, Girl likes boy, follows boy into jungle. Rich guy leads expedition to find girl, who he's going to marry. He falls into...mud.

Oh how I wish I could be a movie villain who gets punished, these are some good memories

Gangster at the end of Cop and a Half gets covered in fish guts that goes up to his chin.

A shy and handsome boy is a victim of a bully boy, but in this time an angel will help him. And de bully boy is covered with food and get a public humiliation:
https://www.youtube.com/watch?v=UCxdWdbgxh0

A bully boy covered first with mud and and after with smoothie:
https://www.youtube.com/watch?v=OUmTOQMa4M4

The first one is "The Heavenly Kid"

The second one is "Christmas Every Day"

The villain in the movie Dadnapped gets really messy, especially towards the end.

The best punishment for an arrogant and stupid nobleman: face plunge into the manure.

Dragonheart: A New Beginning (2000), actor: Tom Burke.