How to Clean a Bottle Brush | Sanitize It Right

For the full breakdown, see our best Bottle Cleaning Brush guide.

Most people rinse a bottle brush and call it done, but that leaves milk residue and bacteria hiding in the bristles. For parents, the stakes are higher than just a clean brush — a properly sanitized brush keeps feeding items safe, and the CDC has specific guidance on how to handle both regular washing and deeper sanitizing for infants.

Why Your Bottle Brush Needs More Than a Rinse

Bottle brushes trap milk, formula, and food residue deep in their bristles. Warm water alone won’t break down the fats and proteins that cling there. Over time, that residue becomes a breeding ground for bacteria that transfers right back onto the bottles you think you’ve cleaned.

Standard cleaning is straightforward: rinse off loose residue, wash the brush with hot water and dish soap, rinse thoroughly, and let it air-dry completely. A quick rinse alone leaves a film of soap and milk behind — the brush needs a full wash with soap to cut through the grease, and a complete air-dry to keep bacteria from multiplying in trapped moisture.

What the CDC Says About Infant Feeding Brushes

For families using bottle brushes for infant feeding, the CDC’s cleaning and sanitizing guidance draws a clear line between daily washing and deeper sanitizing. Daily washing means rinsing the brush well after each use and washing it with soap and warm water every few days — or in the dishwasher if the brush is dishwasher-safe.

For higher-risk infants — those under 2 months old, premature babies, or infants with weakened immune systems — the CDC recommends washing both the wash basin and the bottle brush after every single use. That’s a higher bar than the everyday routine, and it applies until the baby is out of that higher-risk window.

Beyond regular washing, the CDC recommends sanitizing the brush and wash basin regularly, and after every use for those higher-risk infants. Check the brush’s manufacturer guidelines first, since not every brush tolerates every sanitizing method.

How to Deep-Sanitize a Bottle Brush

Check the product’s packaging or documentation before choosing a method.

Use tongs to remove everything afterward.

Steam: Use a dedicated electric steam sterilizer or a microwave steam bag, following the unit’s instructions and the brush manufacturer’s approval.

Rinse thoroughly with cooled, boiled water afterward.

After any sanitizing method, drip-dry the brush and wash basin on a clean, unused dish towel or paper towel in a spot protected from dirt and dust. That careful drying matters as much as the sanitizing step itself.

Common Mistakes That Ruin a Bottle Brush

Three habits cause most bottle brush problems. Storing the brush while it’s still wet traps moisture in the bristles and invites mold and bacteria. Skipping the rinse after each use lets milk dry into a stubborn film that no amount of soap easily removes. And using a sanitizing method the manufacturer never approved — like boiling a brush that’s not heat-safe — can warp or melt the bristles.

Before you boil, steam, bleach, or dishwash, confirm the brush is marked dishwasher-safe or the manufacturer explicitly allows that method. The tool should get replaced every few months or whenever the bristles start looking frayed and matted — a brush that can’t reach the bottom of a bottle is no longer doing its job.