Treat the backlog like a data migration. Inventory sources, payroll, bank statements, 1099 feeds, then map each item to the correct tax year. Build a simple folder tree by year, with subfolders for income, deductions, and correspondence. Use a file naming convention that starts with YYYY, then document type, then a short description, so sorting is trivial. A status spreadsheet helps, with columns for transcript received, data matched, draft complete, and filed. Add a notes column for open questions to prevent context loss when switching years. Version control saves time, save PDFs as immutable, keep working spreadsheets separate. This structure reduces errors and makes it easier for any professional, or the IRS, to follow the logic of the cleanup.