Why does clearing cache leave some cache files?

[joe at actionline.com]

I just cleared cache, then ran a check for large files
and some large cache files still show up ... why?

./.cache/google-chrome/Default/Cache/data_1
./.config/google-chrome/Default/Application Cache/Cache/data_3
-rw------- 1 joe 113254400 Aug 28 22:39 data_3
-rw------- 1 joe    524656 Aug 28 22:42 index
-rw------- 1 joe  29368320 Aug 28 22:42 data_2
-rw------- 1 joe  16621568 Aug 28 22:42 data_1
-rw------- 1 joe   1335296 Aug 28 22:42 data_0