CHICAGO (CBS) — Crews were busy cleaning up Grant Park on Monday, the morning after Lollapalooza wrapped up four days of music and festivities on the city’s lakefront.

The grand task got underway overnight, shortly after the four-day music festival ended, and organizers already were looking forward to next year, tweeting out a quick video about Lollapalooza 2018 early Monday.

Breaking down the Lollapalooza stages was in progress Monday morning, as crews also cleaned up all the trash littering the fields at Grant Park.

The cleanup at Grant Park was expected to take a few days. Some streets around Grant Park will be closed until Thursday – including Columbus from Monroe to Roosevelt, and Balbo, Jackson, and Monroe from Columbus to Lake Shore Drive.

Some music fans had a bit too much fun, by the looks of the Lollapalooza lost and found. The festival’s website shows more than 800 unclaimed items – including keys, wallets, cell phones, and more – with cleanup crews likely to find more as they go.

The city’s Office of Emergency Management and Communications also has reported 234 medical transports during the festival, and 27 arrests, mostly for battery, trespassing, and drug charges. Another 29 people received citations, largely for trespassing by jumping the fences to get into the festival.

Repairs to the grass at Grant Park were likely to be necessary, after heavy rain brought an early end to the first day of the festival, leaving large muddy patches.

Lollapalooza’s organizers are responsible for paying for any necessary repairs at Grant Park. Last year’s bill for repairs topped $450,000.