I've tried almost every trick in the book trying to get blades to last longer. In my experience NOTHING works! If you shave with your blades they will get dull no matter how you dry them, dunk them in oil or alcohol, smear goo on them, whatever. If you don't want your blades to dull then don't shave with them.
The biggest factor I found in my blades lasting longer was improved technique. The better your technique the more the blade will cut your beard rather than scrape your beard. Like shaving with a straight razor bad blade angle makes your blade dull more quickly. Good blade angle is easier on the blade. Even still the most I can get out of a blade is a week and by that 7th shave you know it's time to change the blade.
TOFLAC-U, AOM, LEMS/ Stay back! I have a Merkur, and I know how to use it!