Nuby rapid cool

I wouldn't fully submerge it I usually wash around the inside bit of the lid with hot soapy water and float it on some Milton solution to sterilise it. X

I’ve always washed it properly, fully submerged it in a washing up bowl and never had any issues x

My partner fully washes ours and never had any issues with it.

I usually just wash it with a sponge but outside the washing up bowl x