I’m working on high-entropy oxide (HEO) synthesis via planetary ball milling, using zirconium dioxide (ZrO₂) jars and balls. After milling, I observe that the oxide powders adhere strongly to the inner walls of the jar and are difficult to remove—even with considerable mechanical effort.

So far, I have tried:

• Dry milling with sand
• Wet milling with sand + isopropanol (IPA)
• Manual scrubbing with solvents like ethanol and acetone

Despite these attempts, significant residue remains, especially after prolonged milling runs. Anyone suggest me an effective cleaning procedure