| | Safe? | Better Alternative | | --- | --- | --- | | Liquid Plumber / Drano | ❌ Not for outdoor drains with soil contact or storm discharge | Enzyme cleaner (Bio-Clean) | | Sulfuric acid drain cleaner | ❌ Extremely hazardous – melts PVC fittings | Mechanical auger | | Bio-enzyme cleaner | ✅ Safe – digests grease, soap, organic matter | Use monthly for maintenance |