Give someone the brush-off
is an idiomatic way of detaching from their company.

As daft as a brush
is a simile.  A sweeping brush has no sense, being an inanimate object!

Living over the brush is living together without being officially married.

Let the dust settle.
This is advice to wait until there has been time to recover from an upset.

We couldn’t see them for dust.
They disappeared quickly (as if they were hidden by the dust they kicked up on a dirt track). 

Cleanliness is next to godliness.
This is an old saying.  Godly people should look after themselves and their surroundings.

A lick and a promise describe a quick wash.

Sweep it under the carpet means hide something which perhaps should be dealt with properly. 

A dust up is a fight or disturbance.  (Oxford Concise Dictionary)

A blanket statement is a generalisation.

To soft soap someone is to use persuasive flattery and is similar to buttering them up.

There’s water in the tap!
A response to adolescents complaining that they are thirsty. 

A water-tower is a tall building with a reservoir at a higher level than the surrounding properties.  Water does not flow uphill!

A drinking fountain used to be provided in many public places.

Jesus said, Whoever drinks the water I give him will never thirst.  Indeed the water I give him will become in him a spring of water welling up to eternal life.  John 4:13-14 The context of this saying may be found in John 4:1-42