[css] What methods of ‘clearfix’ can I use?

Using overflow:hidden/auto and height for ie6 will suffice if the floating container has a parent element.

Either one of the #test could work, for the HTML stated below to clear floats.

#test {
  overflow:hidden; // or auto;
  _height:1%; forces hasLayout in IE6
}

<div id="test">
  <div style="floatLeft"></div>
  <div style="random"></div>
</div>

In cases when this refuses to work with ie6, just float the parent to clear float.

#test {
  float: left; // using float to clear float
  width: 99%;
}

Never really needed any other kind of clearing yet. Maybe it's the way I write my HTML.