here is the work around if you plan to do it manually.

start with listing email queue in the server, by using the command exim -bp, it will list all the email currently queue in the server. but my only concern is frozen email in the server, which I would like to manually clean it from the queue. let try something here,

exim -bp | grep frozen

18d 24K 1JhiI4-00096B-OW <> *** frozen ***
18d 2.3K 1JhiII-00097Y-8s <> *** frozen ***
16d 2.8K 1JhiKM-0009AL-9M <> *** frozen ***
15d 2.3K 1JhiLO-0009Bs-EF <> *** frozen ***
15d 2.5K 1JhiLS-0009Bx-O2 <> *** frozen ***
12d 2.7K 1JhiNm-0009S5-AQ <> *** frozen ***
10d 3.3K 1JhiPv-0009aN-Vu <> *** frozen ***
10d 24K 1JhiQ9-0009as-4R <> *** frozen ***

There are the emails currently queue in the server, and now you might want to check why did the email was queue in the server by exim -Mvl

2008-04-02 15:58:52 Received from <> H=(xxx.xxx.net) [202.76.234.132] P=esmtp S=2143 id=20080402075613.8287E22E8BB@xxx.xxx.net
2008-04-02 15:58:52 routing failed for rsvundet_2002@xxxx.com.my: User account not exist
*** Frozen (delivery error message)

If you want to remove all the email from queue more than 18 days, try this command;

exim -bp | grep 18d | awk ‘{ print $3 }’ | xargs exim -Mrm

Message 1JhiI4-00096B-OW has been removed
Message 1JhiII-00097Y-8s has been removed
Message 1JhiKM-0009AL-9M has been removed
Message 1JhiLO-0009Bs-EF has been removed
Message 1JhiLS-0009Bx-O2 has been removed
Message 1JhiNm-0009S5-AQ has been removed

some usefull queue commands:

-bp : Queue email in Server
-bpc : Count Queue email in Server
-M : Force delivery
-Mar : Add recipient
-Meb : Edit message body
-Mes : Edit sender
-Mf : Freeze message
-Mg : Give up (and bounce message)
-Mmad : Mark all recipients as delivered
-Mmd : Mark recipient as delivered
-Mrm : Remove message (no bounce)
-Mt : Thaw message
-Mvb : View message body
-Mvh : View message header
-Mvl : View message log

enjoy and happy cleaning queue email!

Links

Exim Cheat Sheet by bratthemad
Last update: 20080721