I would like to clear out my orders daily. Can I just download all the log,order and tmp files to my computer, then delete them off the server? Is there any problems with in process orders?
Yes, you can delete the "ushop-customers.log" and the "ushop-inventory.log" everyday if you like. You can also turn customer and inventory logging "off" via the uShop Control Panel if you don't use/need the log files.
You can also delete the order files every day ... and that can be done via the uShop Control Panel's "Order Reader" or by ftping/telnetting to your server and manually deleting the .order files.
.tmp files dated older than a day should be rare... but can also be deleted.
Other .log files (other than the afforementioned "ushop-customers.log" and the "ushop-inventory.log") should not be deleted.