Question: Is it possible to purge local caches?

[Zhaph]

We're using v1 on our Umbraco 7 instance quite happily, but have a quick question:

Our client has noticed that an important, legal PDF that they're hosting doesn't open properly in Legacy Edge browsers, and would like to "in-place" replace it - i.e. update the file in the blob storage backing store, and have that served instead, rather than update the many possible links to the document on their site (I appreciate that this link should really be a setting or other shared value we can update as needed and have suggested this going forward), but I wanted to see if there's a good way to purge/clear the local caches that are used by the web apps?

As a further complication, the site is hosted on Azure Web Apps, so we don't have easy access to each instance's machine temp.