Dolores Park covers about 16 acres between 18th and 20th streets, running from Church Street across to Dolores Street. On a warm weekend it holds thousands of people at once, and it stays pleasant only because the people who come here take care of it. A few minutes of planning before you leave the house saves everyone else, and you, a lot of mess later.

• A refillable water bottle. Drinking fountains are scattered around the lawns, and refilling beats buying one more bottle on the way in.
• A reusable cup and a fork or spoon. Food and drink packaging makes up roughly two-thirds of the litter picked up on San Francisco streets and in its parks, so carrying your own cuts the single biggest part of the problem.
• Your own bag for trash and recyclables, in case the bin nearest your blanket is already full.
• Layers and sunscreen. The park can be foggy and windy at two in the afternoon and blazing an hour later.
• A blanket or a low chair, so paths and stairways stay clear for the people walking through.
• A bike lock if you ride in. Bikes belong on the paths, never on the grass.

• Glass. Glass bottles and glass containers are not allowed in San Francisco parks. Aluminum cans and re-usable cups are the better call: cans are lighter to carry, safer on bare feet, and worth more when they are recycled.
• Charcoal grills and open fires. Grilling is limited to designated areas, so check the current park rules before you haul a grill up the hill.
• Anything you cannot carry back out, including the packaging and boxes your picnic arrived in.
• Styrofoam and single-use plastic.
• Amplified sound systems that need a permit, and anything that blocks a path or a stairway. Those are the park's emergency routes.

Every Saturday, Sunday and holiday from 12 noon to 8 p.m., volunteers and staff set up at the corner of 19^th and Dolores streets, right beside the J-Church stop. Bring your cans, bottles, compost and landfill garbage over and the crew will help you sort it into the correct bin. It takes a minute, and it keeps a surprising amount of material out of the landfill. If the can next to your spot is overflowing, please do not stack bags on top of it or leave them on the grass. Walk your trash to the corner instead.

The park is open from 5 a.m. until midnight. Dogs need to stay on a leash everywhere except the designated dog play area on the upper terrace. The tennis and basketball courts, the soccer field and the Helen Diller playground at the north end are shared spaces, so give other people room. Public restrooms sit by the playground. Please do not feed the gulls. They learn fast, they will tear open a bag left unattended within seconds, and the mess they leave behind is the hardest in the park to clean up.

Muni's J-Church line runs along Church Street and stops at the top of the park. BART at 16th Street Mission puts you about three blocks away. The 14 and 14R on Mission, the 22 Fillmore, the 33 Ashbury and the 24 Divisadero all pass nearby. Street parking is scarce on sunny weekends, and traffic around 18th Street is slow, so transit is genuinely the easier option. If you drive, plan on walking a few blocks and never leave anything visible in your car.

Afternoon weather turns quickly. The wind picks up, the fog comes over Twin Peaks, and the park empties faster than it filled. That is the moment most of the litter happens: people leave in a hurry and walk away from blankets, cups and half-finished food. Before you head out, take one slow look at your spot. Everything you carried in should either go back in your bag or go to the Eco-Popup, and the park should look as though nobody was ever there.

Cleaning up after a busy weekend costs the city roughly $750,000 a year, and every bit of it comes out of the same public purse that funds the playgrounds, the courts and the lawns. That is the whole point of the pledge: download, print and decorate your own LOVE DOLORES sign, take a photo with it, and post it with #lovedolores and #dolorespark. You can also share it in the Love Dolores Gallery. Then put the sign in your bag, pick up your trash, and enjoy the rest of your afternoon. That is all it takes.