Can I remove #sql_ .MYD files?

Question

I found some old files in the mysql datadir:

-rw-rw----  1 mysql mysql     0 2012-10-09 09:39 #sql_263c_0.MYD
-rw-rw----  1 mysql mysql  1.0K 2012-10-09 09:39 #sql_263c_0.MYI
-rw-rw----  1 mysql mysql     0 2012-10-09 09:40 #sql_263c_1.MYD
-rw-rw----  1 mysql mysql  1.0K 2012-10-09 09:40 #sql_263c_1.MYI
-rw-rw----  1 mysql mysql     0 2012-10-09 09:40 #sql_263c_3.MYD
-rw-rw----  1 mysql mysql  1.0K 2012-10-09 09:41 #sql_263c_3.MYI
-rw-rw----  1 mysql mysql  338M 2012-08-21 15:54 #sql_3e03_0.MYD
-rw-rw----  1 mysql mysql  1.0K 2012-08-21 15:52 #sql_3e03_0.MYI
-rw-rw----  1 mysql mysql  694M 2012-08-21 15:54 #sql_3e03_12.MYD
-rw-rw----  1 mysql mysql  1.0K 2012-08-21 15:46 #sql_3e03_12.MYI
-rw-rw----  1 mysql mysql  756M 2012-08-21 15:54 #sql_3e03_13.MYD

I have no idea how does it created, maybe temp tables ? Is it possible to check the files still used by mysqld or can be remove ?

My version is: Server version: 5.0.45-log Source distribution