Default [Q] Changing Kernel Configs, not picking up changes?

Hi all,

If I modify the kernel/arch/x86/configs config (manually), how do I get it to pick up the changes without doing a full 'make clean' in the root repo directory? If I just wanted to 'mm' in kernel or something, is there an easy way to do this? I've never understood how this works, and what the hell 'make mrproper' actually does. I've tried googling this quite a bit, but haven't found anything that actually explains it all well. Could someone help me out?