from nscache's README:

NScache is simple program for viewing and amanging contents of Netscape(tm)
browsers cache directory.

It have very easy user interface writen by using of GTK+1.2 widget libraries.
It shows 3 levels tree of cache contents. At first level are protocols, at 
second level are servers and at third level are regular documents.

For each document there is shown its URL, name of cache file, its size, 
MIME type, encoding type, character set for HTML documents, modification
time, access time and time when document expires.

When you press right mouse button inside tree list, you can make any action
on selected item. You can save file from cache to other location, you can 
remove files and entries from chache (one or all entries for server), or you
can compute numbers of documents in subtrees and size of all documets in 
subtree. You can launch any viewer command on cache file or on source URL.
The viewers you can assign to any MIME type. You can also copy selected URL
to clipboard.

WWW: http://www.idata.sk/~ondrej/nscache/