You can use dish washing liquid to clean baby bottles.
Remember to rinse the bottle and nipple with water as soon as baby finishes the feed. Then fill the sink or a vessel with hot water and put in few drops of the liquid dishwashing and let it soak for some time. After that clean with a bottle brush and also make sure the nipple is clean. Remember to rinse it nicely so that there are no traces of soap or any harsh chemicals. And as usual sterilise it before use.You can also use dishwashing liquid that are specific to clean baby bottles if you can get it , Or use a mild detergent rather than a harsh one.