Make page to tell browser not to cache/preserve input values

Are you explicitly setting the values as blank? For example:

<input type="text" name="textfield" value="">

That should stop browsers putting data in where it shouldn't. Alternatively, you can add the autocomplete attribute to the form tag:

<form autocomplete="off" ...></form>

From a Stack Overflow reference

It did not work with value="" if the browser already saves the value so you should add.

For an input tag there's the attribute autocomplete you can set:

<input type="text" autocomplete="off" />

You can use autocomplete for a form too.

Another approach would be to reset the form using JavaScript right after the form in the HTML:

<form id="myForm">
  <input type="text" value="" name="myTextInput" />
</form>

<script type="text/javascript">
  document.getElementById("myForm").reset();
</script>