I've had 3 silkies go broody without fertilized eggs. I used the same method for breaking their broodiness each time.
Sitting in a cool bath for several minutes, cool bath, a wire-bottom cage elevated on bricks with a fan blowing on her for a day,
a cool bath the same evening, with a fan again, a wire-bottom cage for 2 more days, and no access to the nest boxes. --here are my results:
Blue Silkie: Went broody and I noticed it immediately, pulled away the egg, used my breaking method, and two days later, she resumed laying regularly.
She still makes the broody clucking sound, but is non-broody otherwise. She's 6 months old.
Buff Silkie: Went broody after laying an egg in the coop late evening. She sat for 12 hours before I found the egg & broke her.
I used this method, and she stopped making the broody cluck on Day 3, but after a month, has not resumed laying. She's 8 months old.
Black silkie: Went broody after rasing a clutch of 2, and had resumed laying for a week.
I had rehomed one of her chicks and she went broody the next day. I took away the egg within an hour, used the same method,
and she also stopped making the broody cluck Day 3 & seems like she's trying to lay on Day 4.
My conclusion is... the sooner you break her, the more likely you are to get your layer back. This is based on 3 hens, of course.
I have 9 silkies, 3 cochins, so I'm sure I'll be much better at broody-breaking soon, lol.
Good luck!