I caught the tail end of The Martha Stewart Show yesterday (Wednesday 9 April 2008 episode), where she was describing how to clean secateurs (pruning shears, bypass shears, whatever you want to call them!).
So after I’d finished doing some gardening this morning, I followed her simple instructions and cleaned up a couple of pair very quickly and easily. Her secret: lemon juice, salt, and a cork!
Rub a little lemon juice on the blades, sprinkle a little coarse cooking salt over the lemon juice, then rub the lemon and salt mixture into the blades with the end of a cork from a wine bottle—the cork protects your hands and adds a slight grittiness to the mix too. A bit of scrubbing with this mixture and even the stubbornest plant stains come off the blades. Wipe off the mixture after you’re done.
Then to protect the blades and prevent corrosion I squirted a drop of olive oil (any oil should work) on the blades and wiped them clean, leaving enough oil on the blades to protect them.
It works a treat. Think of it as salad dressing for your tools.
Oh, and I added this information to the Wikipedia article on secateurs as there was so little on their maintenance. My good deed for the day!