- I love those rocks, yes, they're my friends.

I've known them forever, so I take it very personally when people deface them and put terrible things on them.

- [Pamela] Artist Holley Flagg has good reason to be protective of the picturesque rocks that define the 400 miles of Rhode Island's rugged coastline.

It's the view right outside the window of her third floor studio, in the home her family has lived in for generations.

This was her childhood playground.

- Grew up there, picnicked there, ran all over the rocks, know them like the back of my hand.

Also, I'm an artist, so I really love the beauty of them, they're just unique rocks.

- [Pamela] Raw natural beauty is the bedrock of Flagg's work.

She's currently painting watercolors of Nebula from images captured by NASA's Hubble Space Telescope.

- This is Madam Butterfly.

- [Pamela] Flagg is also a graphic artist, creating designs for the Metropolitan Opera and the Museum of Natural History in New York.

But when so-called "street art", spray painted graffiti, began proliferating along the rocks in her Narragansett neighborhood, the artist saw red.

(waves crashing) - When you see somebody defacing them and writing their personal messages, which they think are going to be immortal all over the rocks, it's really upsetting to me and it's visceral.

- [Pamela] Flagg was so outraged, she took justice into her own hands, forming the citizens group, Anti-Graffiti Vigilantes.

- Just lightly brush over it like this.

- Armed with only a brush and cans of latex house paint, she started taking a swipe at what she views as crimes against nature.

But what might critics think of their attempts to obscure the colorful doodles of others?

You see this as restoration of nature, others might see it as destroying urban art.

They say graffiti is an art, what do you say?

- I say, go somewhere else and do your urban art.

And some people do really fabulous art, and I respect that and I admired it, just not in nature, let nature be nature.

Let's see what color you got, that's, ooh, it's good.

- [Pamela] Soon a small posse of like-minded volunteers took up the charge.

Their restoration of these geologic gems requires wiping out the words and pictures in such a way it tricks the eye.

Instead of just a coverup, the rocks magically appear as they once were.

- I judge how close I am with the color that I've put on, really the key to a good job is to just feather it in really lightly, let the texture of the rock come through.

- [Pamela] At first, in an effort to be truly natural, the Anti-Graffiti Vigilantes tried to clean off the spray paint with wire brushes, even chemicals, nothing worked because the rocks were too porous.

The beach was too steep for sandblasting equipment, so.

- I know about painting and colors and nuance, so we said, "Let's try, let's try painting over it, camouflage."

- How did you come up with this technique of camouflage?

- I didn't really think about it, I mean, it's just very basic.

How do I make this look like the rock there?

I keep adjusting my paint colors as I go along.

You keep doing it until you like the effect that you've gotten.

- 'Cause the rocks are different, some are granite, some are brown so you have to pick the colors?

- Yeah, and you do many colors over one little area of rock.

You don't just say, okay, this rock is gray, here's gray.

- Get a big dry brush and you just smash it into the rock.

I think it's more just feel than anything.

- [Pamela] Joan Pavlinsky is a social worker, artist, and ardent Anti-Graffiti Vigilante.

- It's just a way of kind of making my own mark by marking over other people's work.

If you think about what art really is, it's mark making, you know?

And hopefully we're creating an environment so that it's not going to be, you know, vandalized again.

- If we do a good job, then they can't tell where it was.

So that's what we're hoping, that as you walk around here, you don't even think about the graffiti, it's just not what you came here to see.

- [Pamela] Volunteer Marianne Chronley joined the Anti-Graffiti Vigilantes a decade ago.

(bee buzzing) Spring and autumn, the band of avengers attack rocks at places like this, along Black Point Trail at Scarborough North Beach, near the iconic remains of the 19th century mansion, Windswept, itself the victim of vandals.

Chronley says they gather tips from informants.

- We watch for it, you know, and we hear about it, people tell us about it.

When we hear that it's down here, we say, "All right, we gotta get a crew together and come on down."

- [Pamela] The Anti-Graffiti Vigilantes go to great lengths to disguise the work of vandals, sometimes hiking through outcroppings and sea spray just to reach their targets.

- We have a large canvas, you know, a large graffiti canvas, and you're like, oh, you know, this is gonna take forever.

It's just like there's no way we can do this.

Within like an hour or two, it's done.

And you sit back and I am often amaze myself.

- [Pamela] These before and after pictures are testimony to the results.

Some photos we can't share because of objectionable words and images.

- Last thing you wanna do when you had a hard day at work, you're out with your dog, you're out with your kid, you're walking along the path and you see a large pink profanity like written on a rock, you know?

It's like, it just sort of just creates this energy that just drains you, I think.

- [Pamela] The Anti-Graffiti Vigilantes say, "Those who come to stroll along the shore often voice appreciation and sometimes offer to help."

- A lot of people say, "Oh, I'm so glad you're doing that."

They sympathize and they totally agree with how we feel.

And then other people are totally blank, they have no clue what we're doing and they just think there's a bunch of weird people.

- [Pamela] Undaunted, the graffiti vigilantes keep chipping away, true rock stars of Rhode Island's shores.

- It's with great satisfaction, so as I step over some of the rocks, I can think, ah, we've been here and we did that one, and we've done that one many times, we'll probably have to do it again.

But it's nice to know that we were here and it looks better now.

- I want you to be able to look at these beautiful rocks and not read things.

No words, no images, just say, "Wow, these rocks are really beautiful, this ocean is beautiful, and we are so grateful to have it."

(waves crashing) - Aw, a beautiful ocean state.