Outlook Express Temporary File Directory

I'm running, and have been running OE6 on my old XP computer for years. But recently I'm getting Low Disk Space errors. The drive has 1g of disk space available, and I cannot find where this Temp File Directory is located so I can clean it out; must have tens of thousands of e-mail copies in there since I get 200 e-mails a day. Anyone know where this temp file directory is located on an XP PC running OE6?