Common areas of a building

[Maya Jones]

Chicago Landlords,do you send notice to enter common areas? does the same rule as entering the unit apply? 
What if the tenant is using common areas to store personal stuff and pluggins appliances like mini fridges? 
how do you tell them nicely to vacate the area and stop using electrictiry from common area?

or do you just let it be? i don't have a special contract with nice addendum, its the standard Chicago one