What's the best style to clear a drain? ...

Want to repair tub tub?
Answers:    depends which drain it is, inside and out.. and what it's blocked with..

if it's a sink.. try the trap beneath the sink.. or using a plunger or sink/plug hole un blocker.. the shower here gets blocked over time.. but I only plung it and it's fine again.


other things like soda crystals are biddable for outside drains..

but maybe it requirements rods ..or more expensive jet wash.

depends whats blocked the drain.. it might have to be removed and binned if it's not juice..

the sewers are full of chip fat / butter.. as that gets cold that turned into white lumps of corpulent.
Best cement?
Try drain rods first,if no joy afterwards use a pressure washer.