Well said Boing7117 - the last bit is very true. Someone above said that it made no sense to prepare long and hard for day 1 and 2 and go to the sim rusty. So a few hours to remove that would certainly be advisable, however my advice would be to ensure you show improvement during the sim. I'm sure they want to see that you have good CRM and just as important, that you are trainable. They are investing a type rating in you most likely, so showing improvement I think looks far better then flying like an ace who's had numerous hours practice prior to the assessment.