Headers not clearing

I'm not sure what is going on here since I had it working before, but headers aren't clearing properly:

    more_clear_headers   "Server:*";
    more_clear_headers   "X-Page-Speed:*";
    more_clear_headers   "X-Powered-By:*";
    more_clear_headers   "X-CF-Powered-By:*";

Is what I tried, but the the headers are still appearing. I tried restart nginx multiple times with different configurations:

    more_clear_headers   "Server: ";
    more_clear_headers   "X-Page-Speed: ";
    more_clear_headers   "X-Powered-By: ";
    more_clear_headers   "X-CF-Powered-By: ";

and
more_clear_headers "Server:";
more_clear_headers "X-Page-Speed:";
more_clear_headers "X-Powered-By:";
more_clear_headers "X-CF-Powered-By:";

Here is Nginx -V:
nginx version: nginx/1.6.0
built by gcc 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5)
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_random_index_module --with-http_secure_link_module --with-http_stub_status_module --with-http_auth_request_module --with-mail --with-mail_ssl_module --with-file-aio --add-module=/tmp/nginx-1.6.0/debian/modules/ngx_pagespeed --add-module=/tmp/nginx-1.6.0/debian/modules/headers-more-nginx-module --with-http_spdy_module --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro' --with-ipv6

I'm using Ubuntu 12.04 with Nginx 1.6.0. Thanks!

Start with the reported nginx -V output and the three configuration variants shown in the issue, then inspect how headers-more-nginx-module handles these directives in the relevant configuration context. Done means identifying why the listed headers remain present and documenting a reproducible configuration or module-level fix.