I've found that the "foaming" drain cleaners (normally a container with two different chemicals that mix as you pour) work pretty well for drains that aren't really blocked but could do with clearing. If it's not blocked then normal drain cleaner seems to wash straight down.
I've found that the "foaming" drain cleaners (normally a container with two different chemicals that mix as you pour) work pretty well for drains that aren't really blocked but could do with clearing. If it's not blocked then normal drain cleaner seems to wash straight down.
This kind of thing https://www.amazon.co.uk/Mr-Muscle-Drain-Foamer-500ml/dp/B000TAPCQ8 Although it's often on special offer for a few quid.