getting the blank clean under the seat is ok but not necesary ( a new reel seat will cover the mess up)

also if you cut the cork make sure you dont go to deep, your pretty much going to have to chip away at it. Then when most of it is all off just sand the rest away. Again its not necessary to get all the way down to the blank, but close is good.

With the guides, a little heat will go a long way, the heat will soften the epoxy and make removing them and the thread easier. When the guides are off try cleaning the blank with alcohol and a finger nail or fake credit card.