Zero Width Space Characters

Hi there,

I'm having an issue, where a client is pasting in text from Word -> TextEdit -> Perch text field yet this strange character seems to be sneaking into the field and because I'm generating a slug from the title, the url is giving me a 404 error. I only found it it was called a 'Zero Width Space' by pasting it into some converter online. I'm wondering if there is a good way to strip these out, I thought replace might be the short term answer but I've never come across this issue before.

I've attached my template and diagnostics below, hopefully they can shed some light (and not reveal how messy my code is!).

Thanks!

Template:

<article class="h-entry">
    <h1>
        <a href="<perch:content id="slug" type="slug" for="postDateTime_year postDateTime_month postDateTime_day postTitle" suppress="true" />" rel="bookmark" class="p-name">
            <perch:content id="postTitle" type="text" label="Title" required="true" order="1" title="true" />
        </a>
    </h1>
    <perch:if exists="image">
        <div class="image">
            <img src="<perch:content id="image" type="image" width="360" height="225" crop="true" />"
                 srcset="
                    <perch:content id="image" type="image" width="360" height="225" crop="true" /> 360w,
                    <perch:content id="image" type="image" width="640" height="400" crop="true" /> 640w,
                    <perch:content id="image" type="image" label="Image" width="844" height="528" crop="true" order="4" help="Upload or select an image, minimum size: 860px wide." /> 844w"
                 sizes="(min-width: 40em) 75vw, 100vw"
                 alt="<perch:content id="postTitle" type="text" />" 
                />
        </div>
    </perch:if>
    <div class="description e-content">
        <perch:template path="content/buildable_inner_page.html" />
    </div>
    <hr>
    <div class="meta">
        <time class="dt-published" datetime="<perch:content id="postDateTime" type="date" label="Date" time="true" format="Y-m-d H:i:s" divider-before="Meta information" />">
            <perch:content id="postDateTime" type="date" time="true" format="%d %B %Y" required="true" />
        </time>
        <perch:related id="author" collection="Authors" label="Author(s)">
            by <span class="p-author h-card"><perch:content id="first_name" type="text" /> <perch:content id="last_name" type="hidden" /></span>
        </perch:related>
    </div>
</article>

<perch:content id="excerpt" type="textarea" label="Excerpt" markdown="true" order="3" suppress="true" size="s" />
<perch:content id="image" type="image" width="282" height="176" crop="true" suppress="true" />
<perch:template path="content/_content_seo.html" />

Diagnostics:

SUMMARY INFORMATION

Perch Runway: 2.8.13, PHP: 5.6.12, MySQL: mysqlnd 5.0.11-dev - 20120503 - $Id: 3c688b6bbc30d36af3ac34fdd4b7b5b787fe5555 $, with PDO
Server OS: Linux, cgi-fcgi
Installed apps: content (2.8.13), assets (2.8.13), categories (2.8.13), perch_forms (1.8.3)
App runtimes: <?php $apps_list = array( 'content', 'categories', 'perch_forms' );
PERCH_LOGINPATH: /perch
PERCH_PATH: /home/site/public_html/perch
PERCH_CORE: /home/site/public_html/perch/core
PERCH_RESFILEPATH: /home/site/public_html/perch/resources
Image manipulation: GD Imagick
PHP limits: Max upload 256M, Max POST 256M, Memory: 256M, Total max file upload: 256M
Resource folder writeable: Yes
DOCUMENT_ROOT: /home/site/public_html
HTTP_HOST: site.com
REQUEST_URI: /perch/core/settings/diagnostics/
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php