Need to Combine different cells into 1 column

[karthisiva]

Hi, i have a sheet with data in columns from a to somewhere to z this varies...

in every column, few cells will be highlighted to red for us to indicate those were out of stock and we need to remove those, i want to know how i can combine all the red cells from a to z column into 1 single column or even in sepeerate sheet etc.,

please help me