Clearing texture memory upon removing a model?

I notice when a model is removed from the workspace that contains textures, or a gui is no longer visible that also contains decals/textures, roblox doesn't delete the data for them although not in use/removed. I don't even know if this is possible, hence no script, I was reading in the wiki about "good practices" regarding textures and lag and all that good stuff. But is it possible to delete the memory from decals/textures being downloaded when they are no longer in use? My texture memory has been the death of my game for mobile users. I've reuploaded all the textures to reduce KB on each individual image but unfortunately it hasn't been enough. In my game, models only appear once another has been deleted behind them, helping in that "brick count" lag but not preventing crashes on account of memory overload because of texture data. I am guessing this might have to be some sort of feature request for roblox. Let me know if I'm wrong and if there is a way:)

Thanks!