Remove block from magento left or right column

In your layout.xml
<remove name="block.name" />

Following code will remove default sidebar blocks:

<default>

<remove name="customer_account_navigation"/><!--Customer navigation-->
<remove name="sale.reorder.sidebar"/><!--Sales reorder sidebar when customer logged in Dashboard-->

<remove name="catalog.product.related"/><!--Related products sidebar-->
<remove name="catalog.compare.sidebar"/><!--Compare product sidebar-->
<remove name="catalog.leftnav"/><!--Layered navigation-->
<remove name="catalogsearch.leftnav"/><!--Layered navigation on search result page-->

<remove name="right.permanent.callout"/><!--Right Callout Sample Data-->
<remove name="right.reports.product.viewed"/><!--Recently Viewed Products-->
<remove name="right.reports.product.compared"/><!--Compared Products-->
<remove name="right.poll"/><!--Poll-->

<remove name="left.newsletter"/><!--Sidebar Newsletter-->
<remove name="left.permanent.callout"/><!--Left Callout Sample Data-->

<remove name="wishlist_sidebar"/><!--Wishlist Sidebar-->
<remove name="paypal.partner.right.logo"/><!--Paypal logo Sample Data-->

<remove name="tags_popular"/><!--Popular Tags-->
<remove name="cart_sidebar"/><!--Cart sidebar-->

</default>