Oxalic Acid (5 Pound) Pure Fine Powder - Multipurpose Cleaner and Stain Remover for Wood, Metal, Stone, Concrete- Rust Remover - Wood Restorer - Deck Cleaner - Industrial Grade Strength

**** The Oxalic Acid 5 lb, boasting 99.6% purity, has garnered mixed reviews from customers, showcasing its potency as both a cleaner and stain remover. Users have praised its effectiveness in tackling tough rust stains, especially on surfaces like bathtubs, where it eradicates decades-old marks. However, with its strong formulation, caution is emphasized, as prolonged contact can create a rough texture, likened to "100-grit sandpaper." In practical applications, many have found success using the product in a diluted form within a spray bottle for various cleaning tasks, notably in marine contexts to address brown stains on boat hulls. Despite this, not all feedback is positive; some customers reported disappointing results when used on ceramic tiles, mentioning a grainy residue left behind, which detracts from the expected cleaning efficacy. Overall, while the Oxalic Acid is celebrated for its strong capabilities in rust removal and multi-surface applications, users should approach with care to avoid surface damage and be aware of potential residue issues on specific materials. **