Why? Old refereces wont go away.

[Eidolon]

I have a web project which had some references to the Crystal
libraries. We were playing around on our DEV server with adding a report
into the web.
Now however, the framework will not get rid of those references. We
have removed them from the project, removed their paths from the
"References" field in Project|Properties. NONE of the project files
reference anything Crystal anymore. Yet the 'Temporary ASP.NET Files'
directory for this project still has the references for Crystal.
We've even gone so far as to shut down IIS on the server, delete the
'Temporary ASP.NET Files' folder, then recompile the project, restart
IIS and let the server recreate the 'Temp' folder. And still the Crystal
references come back.
Why in the world can we not convince the server that we no longer
want those references?

Thanks in advance,
- Aaron.