clear sharepoint property bag cache without apppool cycle

I've inherited code that uses the P&P code for accessing a farm-level property bag property on SharePoint 2013 SP1. The code has an application page to manipulate the property bag, and another application page that uses the values in the property bag.

It appears that SharePoint caches the property bag values - when I change the values in the maintenance page, they are not reflected in the consumer page, until I recycle the application pool.

I've looked a lot and I see people talking about how those values are cached, and some people e.g. Caching mechanism for parameters stored in a web application's property bag talking about doing their own caching, but I don't see any way exposed to flush the cache or the like. The values are changed infrequently enough that a cache flush isn't a problem - but any time we can avoid cycling a SharePoint app pool is a good thing, so we'd like to just force the cache to invalidate.

How do I do that?