disassembly

Took apart gan 249 for some lubing after going 2 years with no lube, trying to put back together, but need some help, can't figure out how to insert corners back into the core since the hole is so small!

I’ve never dissembled a cube above 3x3, but I’m considering replacing a slightly damaged corner on my new QiYi WuJi 7x7. 1. Is the right approach to remove a pair of adjacent edges next to it first—by turning those 2 layers to 45 degrees and... twisting/pulling the 2 edges together as one? 2...