How to Finish a Mahogany Floor | DoItYourself.comYou can eliminate that with a simple spirit cleaner. Always follow manufacturer's instruction, but you can normally apply your finish with a rag or brush to penetrate the wood properly. Step 5 Applying a Sanding sealer sealing is an important step in finishing your mahogany floors if you haven't chosen an oil-based finish. It stops your flooring from absorbing excessive amounts of stain, preventing dark spotting. sealer is applied after you've applied both the stain and grain filling.