How to eject my external drive when my Mac refuses because of Spotlight?

I have plugged an external disk to my Mac. Now, I want to eject it. But my Mac stubbornly refuses and says that an application may be using the disk. I have not launched any app neither opened any file from the disk. [I have downloaded and installed the app *What's Keeping Me?*](http://www.hamsoftengineering.com/products/wkm/wkm.html) This app is quite nice. She tells me that the process mds is using my disk. I have killed the process mds and several processes mdworker. These are for Spotlight. But such processes get spawned again. **How can I eject *my* disk from *my* Mac ?** I have Mac OS X 10.6.8.