Treatment of rental application fees (tax, LLC)

[Bienes Raices]

I'm taking applications for a property owned in an LLC. They are always in cash. Do I need to deposit this cash into the LLC bank account in order to do things the right way in terms of the LLC, or is okay to just keep the cash? (I order my credit reports, etc. on the computer with a credit card, so the cash is not used directly).

I was also wondering if I have to declare these app fees as income on my tax return, since they are going (indirectly) towards the cost of tenant screening (i.e. not profit). Thanks.