Bank statements are the foundation. Every business bank account, for every month you need cleaned up. If you’re missing a month, download it from your bank’s website or request it directly. Without bank statements, cleanup is impossible because there’s no source of truth for what actually happened.

Credit card statements for every business card come next. Same logic applies. If money moved through a card for business purposes, those statements document the transactions. Personal cards used for business expenses complicate things, but bring those statements too and be prepared to identify which charges were business-related.

Your existing bookkeeping records matter, even if they’re wrong. If you have a QuickBooks file, a spreadsheet, or even a shoebox of receipts, gather it all. The catch-up bookkeeping process goes faster when there’s something to reference, even if that something is incomplete or inaccurate. Starting from scratch takes longer than fixing what exists.

Prior year tax returns show what your books should tie back to. The ending balance sheet from last year’s return becomes the starting point for this year’s books. If your books don’t match what was filed, the cleanup needs to reconcile that difference.

Payroll records matter if you have employees. Year-end reports, quarterly tax filings, and payroll register summaries help verify that wages, taxes, and benefits were recorded correctly. If you use a payroll service like Gusto or ADP, they maintain these records online and you can download what’s needed.

Loan statements and agreements document debt activity. Principal and interest portions of loan payments need to be split correctly in your books. The original loan amount and any refinancing affect your balance sheet. Bring statements for the entire cleanup period if possible.

Receipts for major purchases help with asset capitalization. If you bought equipment, vehicles, or other big-ticket items, those documents show purchase dates and amounts for depreciation purposes. You probably won’t have receipts for every small expense, and that’s fine. Focus on items over $2,500.

Invoices and bills help fill gaps, especially for accounts receivable and payable. Customer invoices show what was billed and when. Vendor invoices show what you owed. These reconcile against payments in your bank statements to verify open balances are correct.

The reality is that most people starting a cleanup don’t have perfect documentation. That’s often why the books got messy in the first place. Start with bank and credit card statements because those are always available from your financial institutions. Everything else helps but isn’t always required.

When you work with a bookkeeping service on cleanup, the first conversation is usually about what you have and what period needs attention. Some cleanups require extensive documentation. Others can be done primarily from bank records. What you need depends on what you’re fixing and how far behind you are.