if you're on the page you're working on and clear the cache, it doesn't clear the items on that page. you have to go to some other page, and THEN clear the cache, and then go back to your page.
ANNOYING!!!
but if you use flashobject.js to embed your flash movie i've noticed this is not a problem!
here's example code
<html>
<head>
<title>Here's the title</title>
<script type="text/javascript" src="flashobject.js"></script>
</head>
<body>
<div id="flashcontent">
this show up if the user doesn't have flash or has javascript turned off.
</div>
<script type="text/javascript">
// <![CDATA[
var fo = new FlashObject("mymovie.swf", "fo", 400, 500, 6, "#000000");
fo.write("flashcontent");
// ]]>
</script>
</body>
</html>
but you're gonna need the javascript file I attached. this file is AWESOME! it also fixes that annoying thing in IE having to click to activate the flash.