How to fix CPU-hog Quicksilver

There's one application I particularly love: it's Quicksilver (for Mac).
This week, unfortunately, it started to behave oddly: my PowerBook was continously hot and I quickly found (through Activity Monitor) out that it was Quicksilver's flaw, which was eating 20-90% of my CPU.
I tried to quit and reopen the application, delete the preferences file and to rescan manually my catalog: nothing seemed to work.
After wandering around my Mac's folder for a bit I found the folder containing the indexes used by Quicksilver:
/Library/Caches/Quicksilver/Indexes/
I quit Quickilsilver, moved the folder to the trash and reopened Quicksilver... it worked!
Everything is now back to normal.

A quick explanation Quicksilver builds indexes that make it really fast when searching: they are what makes Quicksilver a pleasure to use.
Considering that I've been using Quicksilver for years, those files might have become corrupted and that was making Quicksilver consuming 20-90% of my CPU.
Clearly the problem was not in the application itself (in fact downloading and reinstalling Quicksilver wouldn't have worked), but it was in some of the files it was using.

One of the most used file is the preferences file ( /Library/Preferences/com.blacktree.Quicksilver.plist ), but deleting it didn't help.
Other files used by Quicksilver stand in /Library/Application\ Support/Quicksilver; but there's another folder used by the application: /Library/Caches/Quicksilver.
You might be wondering "Why isn't the cache in the "Application Support" folder?". It's because cache is something that make the program faster and can exist or not; deleting it might make the application slower but it mustn't affect program settings.
The "Application Support" folder, on the other hand, is used to store customizations of the program, such as plugins, etc...: deleting it would definitely make lose what has been set.