Write a stylesheet with two template rules.
The identity template for elements that you don't want to change:
Code:
<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
and a special rule for the elements you do want to change:
Code:
<xsl:template match="q">"<xsl:apply-templates/>"</xsl:template>