Yes, you can remove trace files, and Orclalrt.log will be used as cronological log for your Database, It generally include messages for Database startup, shutdown, Log switch.

You can also remove Orclalrt.log file, but truncating from the beginning will be a good practice. If you remove it Oracle server will create one.

To know position of these files check parameter BACKGROUND_DUMP_DEST.

Cheers

Dilip.