When you see an image by an artist you dislike, click on the skull to its right. Bookmark the resulting page, replacing any old Sieve bookmark you may have.

To ignore more than one artist at a time, you may use the 'Edit List' selection in the top of the page. Be warned that this gives you a huge page, with one line for every artist on the VCL. It may take quite some time to send and for your browser to lay out. Use the checkboxes to determine who is filtered out, press the 'Okay' button at the bottom, and bookmark the resulting page.

Remember: Always bookmark after changes. The ever-expanding 'l1=blahblah...' part of the URL is the only way the Sieve keeps track of who you dislike; if you do not bookmark, your changes will be lost.