Hi Jasavir,
https://www.gov.uk/government/upload...t_2_Ex_Pub.pdf
FCTM: Clean Cockpit
"Objects not stored in their dedicated area in the cockpit may fall and cause hazards such as damage the equipment or accidentally operate controls or pushbuttons. Airbus highly recommends that the flight crews put and store all objects in their dedicated area in the cockpit:
Cups in the cup holders
Books and paper, if any, in the lateral stowage
Trash in the waste bin in the lateral console
Meal trays on the floor behind the flight crew. The flight attendants should collect the meal trays as soon as possible
Personal equipment properly secured in the various stowage area."