Records to Keep for Income and Expenses-financial tip of the week
What types of records do you need to keep to substantiate your income and expenses?
Both information in your accounting system and supporting documentation will do the trick.
For income, a public charity needs to keep records for all the amounts received from all sources and keep separately all unrelated business income records. Keep documents to show the amount and source of the funds, such as: donor correspondence, pledge documents, cash register tapes, bank deposit slips, receipt books, invoices, credit card charge slips, and Form 1099s. 

http://ow.ly/TTSfC