Question Unconvential material animation issue

So im doing something rather unconventional.
Im using legacy built in renderer and im trying to make animated tiles.
The tiles have animator with a single goal to swap material as if animating.
The reason im swapping materials instead of only texture is because the materials contain also normal and occlusion maps.
The issue this leads to is that with each material swap it loads a new material and stacks it up which leads to memory leak