Wardens are starting a drive to make sure people using a park do not leave litter behind.
Bede Park, off Western Boulevard, Leicester, is a popular spot with students and others when the weather is warm.
But Leicester City Council wardens said a sunny day meant a big litter pick at the end of it.
They have been telling park visitors they could face fines and talking to shops in the area about getting customers to re-use bags.
City warden Richard Sutton, who is responsible for the park, said the aftermath of sunny days so far this year suggested the message was getting through.
He said: "Students and residents often buy their supplies at the supermarkets in the area and take them to the park.
"At the end of the busier days, we have a blitz team that goes around the parks to collect litter but we've also been doing a lot of educating to get people to take their rubbish home.
"I've been talking to shops about how they can encourage people to use bags for life.
"I have been walking around the parks reminding people of their responsibilities. If people are seen littering they will be issued with fixed-penalty notices.
"But we want to get them before that's necessary."
He said the warden team were planning more patrols over the summer and a big education drive during Freshers Week, when the new students beginning their degrees in September and October arrive in the city.
Sarah Russell, assistant city mayor responsible for environment, said new bins were also helping improve the situation in the park, which is in her ward.
She said: "We are working to reduce littering at Bede Park.
"In the past, we did try handing out blue bags for people to take their rubbish home in but we just ended up having to collect more blue bags than rubbish.
"But we now have bigger bins in the park and things are improving."
People using the park welcomed the crackdown.
Tina McDonald, 25, who lives in the area, said: "It can be real mess after a hot day when all the students have been here. They leave food, disposable barbecues, bottles and all sorts."
Greg Stanley, 62, said: "I've not seen any wardens around here but I think it is a bit cleaner that it used to be.
"There are plenty of bins so there's really no excuse for people to be leaving litter around here."
