Unloading webGL components

I have a task which uses playcanvas tasks using iFrames.
The issue is memory consumption in IE11 (Window 10 64 bit) is too high (around 45-50%) even when I close 3 out of 4 iFrames running playcanvas tasks.
This is making tasks very slow.
Is there any method to unload webgl components when I close a iFrame or any other method for lower memory consumption.