I am not sure what log files you are deleting, but you might want to check out logrotate.
If that doesn't work you could do something like this and put in a script and schedule a cron job.
# find files older than 7 days and delete them
find /tmp -type f -mtime +7 | xargs -- rm -f --
Here are the commands that would go with the list you posted.
df = 97% df -h shows disk usage
goto /var/log cd /var/log changes the directory to /var/log
delete *.logs rm *.log removes all files with the extention .log
and reboot reboot reboots the box
If you want to schedule it in cron, here is a how to for cron.
Here are 2 guides for bash scripting.