Over the past three months, Sydney Water crews have had to fix more than 7000 faults in the wastewater network.

Now a new advertising campaign has been launched to remind people that pee, poo and toilet paper are the only types of waste that should be flushed.

Sydney Water's Maryanne Graham says too many "unflushables" are going down the loo and wreaking havoc on the wastewater network. These include jewellery, watches, notes & coins, kids toys such as Lego and figurines, earphones, lighters - and once a brick was found. Other items include wet wipes and oils.

One in two people are flushing the wrong things down the toilet, Sydney Water estimates. And three in four are putting the wrong things down the sink.

Before we get too smug, it's worth remembering all those times Hunter Water had to pull "fatbergs" out of the pipes below Newcastle. Wet wipes are responsible for around 75 per cent of wastewater blockages. Sydney Water said it spends more than $8 million a year removing 500 tonnes of refuse from the wastewater system.

Unflushables include wet wipes, cotton buds, tissues, dental floss, hair, cleaning cloths, and sanitary products.

Unsinkables include fats, oils, and grease as well as other kitchen items like coffee grounds and food scraps.

It was Christmas Day 1946 when notorious Chicago gangster Al Capone took his wife and four granddaughters out for a walk onto the dock of their sprawling mansion at Palm Island, Florida.

A picture shows 'papa', as he was known to them, relishing his freedom after being released from Alcatraz where he had served more than seven years for tax evasion.

That picture is among 174 items belonging to the Capone family that will go up for auction in Sacramento, California, today.

The items range from personal photographs to firearms to pocket watches and jewellery, as well as furniture and kitchen ware.

Diane Capone, 77, the second of Al Capone's four granddaughters, said she hopes the items will reveal the human side of her grandfather, instead of the ruthless violence that plagued Chicago in the 1920s for which he has become infamous.

The item that most exemplifies this, she said, is a personal letter Al Capone wrote to his son, Sonny Capone, from Alcatraz estimated between $US25,000 and $US50,000.

"It's such a lovely letter, and it is a letter that conveys a side of this man that the vast majority of people have no idea of," she said.

"These are not the words or the ideas of a man who is a ruthless gangster. These are the words of a loving father."