What to do if your aroma stone gets moldy? A guide to identification, isolation, and when to stop using it.

First, the conclusion: If your aroma stone shows black spots, white spots, or an off-odor, stop adding fragrance immediately and isolate it from other items. Do not wash with water, spray with alcohol, scrub, or sniff it up close. Dust, stone powder, crystallization, and oil stains can be mistaken for mold; if the spots are velvety, continue to spread, are accompanied by a damp odor, or if the aroma stone has become soft due to moisture, stop using it. Once porous materials like plaster are contaminated internally, it is difficult to ensure they are thoroughly cleaned. If the spots are widespread, recurring, or you are unsure, it is safer to replace the item.

Published: August 30, 2026 09:02 (Taiwan Time)｜Category: Aroma Stone Encyclopedia & Care Guide｜Author: LOX Editorial Team

First, distinguish: Black and white spots are not always mold

Do not judge by color alone. First, consider whether the aroma stone has recently been placed in a bathroom, near a sink, by a window, in a damp shoe cabinet, or splashed with water. Next, observe the surface, location, and changes in the spots. The U.S. EPA points out that controlling moisture is the core of handling mold issues; porous, absorbent materials are sometimes difficult to clean completely and may even need to be discarded. Plaster is porous and absorbs moisture, so the wet scrubbing methods used for glass or tiles should not be directly applied.

Six steps for handling a suspected moldy aroma stone

1. Stop adding fragrance and move away nearby items

Stop adding essential oils or fragrance oils, and move the aroma stone away from wooden tables, fabrics, cardboard boxes, and other aromatic items. If there is oil or water on the base, place it on a clean, oil-proof, independent tray.

2. Wear gloves to avoid disturbing the spots

Do not use hard brushes, sandpaper, or hair dryers indoors. These actions will disturb the surface and may damage delicate relief work. If you can see obvious velvety growth, large patches, or smell an odor, do not lean in to sniff it just to confirm.

3. Check the source of moisture

Simultaneously check if walls, cabinets, trays, and nearby fabrics are also damp. If placed in a bathroom, refer to Moisture-Proof Placement for Bathroom Aroma Stones; if it was exposed to water, follow the steps for Air-Drying an Aroma Stone After Water Exposure to treat the environment, rather than rushing to heat it.

4. Dry and observe in isolation

Place the object alone in a cool, dry, well-ventilated area, avoiding direct sunlight, baking, or placing it too close to the exhaust of a dehumidifier. This step is to stop the accumulation of moisture and observe changes, not to disinfect or restore it to usable condition.

5. Determine if it can be cleaned based on material

Bare plaster, unglazed ceramics, and other porous materials allow liquids and contaminants to penetrate the pores; even if the surface looks clean, it is impossible to confirm the interior with the naked eye. If it is a detachable non-porous tray or glass dome, clean it according to its specific material instructions; do not use the same method on the aroma stone itself. For general cleaning differences, see Can Aroma Stones Be Washed?.

6. Replace if stop-use conditions are met

If the spot area is large, recurring, continues to spread, is accompanied by an odor, or if the stone itself has turned to powder, softened, or cracked, stop using it. If the moisture or mold in your home affects more than just one small item, you should address water leaks and indoor humidity; for widespread issues, seek professional guidance.

How to judge in three actual scenarios

Black spots appear in the bathroom

First, move the aroma stone out of the damp area and check the tray and wall corners. If the spotted marks have velvet, continue to increase, or are accompanied by an odor, stop use immediately; if they are just dry dust, you can clean them according to the Aroma Stone Dust Cleaning Method before observing.

Turns yellowish-brown after adding dark fragrance formulas

Smooth stains that spread along the pores are more likely related to the color of the formula or excessive use. Stop adding fragrance, isolate it from surfaces, and wait for it to fully absorb; do not attempt to bleach it with bleach or large amounts of alcohol.

White spots appear after being taken out of storage

Check if the packaging material was damp, if the white spots are loose, and if there is any odor. Do not add fragrance until confirmed; for future storage, ensure items are dry, packed separately, and refer to the Aroma Stone Storage Guide.

How to reduce the chance of recurrence

• Add only a small amount of fragrance to the back of a dry, clean aroma stone, and let it fully absorb before adding more.
• Use an oil-proof tray to separate it from the surface and ensure adequate ventilation around it.
• Avoid placing it long-term in damp bathroom areas, next to sinks, above damp shoes, or in closed, humid drawers.
• Ensure both the stone and packaging materials are dry before storage; do not seal items that still hold moisture in plastic bags.
• Regularly inspect the surface, base, and crevices visually, rather than waiting until an odor becomes noticeable.

Aroma Stone Mold FAQ

Q1: Can I wash the aroma stone with bleach?

It is not recommended to use bleach as a universal solution for porous aroma stones. Plaster and unglazed ceramics absorb liquids, and the formula may remain, change color, or damage the surface; if the suspected mold area is large or recurring, it is safer to stop using it and replace it.

Q2: Can spraying alcohol remove mold?

Direct spraying is not recommended. Alcohol may affect the surface, formula color, and structural integrity, and you cannot confirm that the pores are clean just because the surface dries. Isolate, stop use, and address the source of moisture.

Q3: Is white powder just white mold?

Not necessarily. Stone powder, dust, or efflorescence can all be white. Observe if it is velvety, continues to spread, has a history of moisture, or smells; if you cannot judge, stop using it.

Q4: Can sunlight kill mold?

Do not use sun exposure to replace treatment. High temperatures and UV light may cause discoloration, cracking, or rapid evaporation of the fragrance; moving the aroma stone to a cool, ventilated place is for dry observation, which does not mean mold removal is complete.

Q5: Can I still use it if there is only one small black spot?

Stop adding fragrance and observe first. If it is dry dust that can be moved, and after cleaning there is no moisture, odor, or signs of regeneration, you may assess its continued use; if the spots are clustered, spreading, or if you cannot rule out mold, do not continue to diffuse fragrance.

Sources and Usage Reminder

This article refers to the U.S. EPA's Brief Guide to Mold, Moisture, and Your Home and Mold Cleanup in Your Home, as well as the Canadian Conservation Institute's Care of Plaster of Paris. This article provides maintenance assessment for small aroma stones and does not replace professional treatment for building leaks, widespread indoor mold, or health issues.