Removing Price History When Selling

[Brad D.]

I notice on some houses listed on Realtor/zillow/redfin, you can see the price history: listed prices, sold prices, price changes. On others, you can see no prices. It simply says 'delisted' or something to effect with a dash.

There's obviously an advantage to sellers in not having this information as readily available. Does anyone know the best way to:

1. Sell a house without having any previous listed/sold/changed prices appear? 

2. Is there a way to remove previous years' listed/sold/changed numbers that currently appear?

3. Approaching from the other end as a buyer: what is the best way to find listed/sold/changed prices for houses that don't display it?