Not sure if this has been posted here before, but this corkscrew works really well for old crumbly, saturated corks.
The Durand corkscrew
Prior to getting this corkscrew, the corks in last couple of older bottles (1970 and 1975) I opened came out in pieces. I got them out but it was tricky and a lot of work.
The two piece Durand combines the benefits of a screw and prongs. It's a bit trick to use at first. The screw needs to be in the center for the prongs to go in correctly. A couple of weeks ago I used the Durand on a 1978 Margaux. The cork came out smooth in one piece despite the age.
I'd recommend this opener for anyone opening bottles older than 20 years on any regular basis. Note that it is designed specifically for old crumbly saturated corks.