Erro ORA-01691 durante EXPDP

Amigos,

Estou realizando um EXPORT de uma base pelo Oracle XE, mas está sendo interrompido com o seguinte log:

Connected to: Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production
Starting "SYSTEM"."SYS_EXPORT_SCHEMA_01": system/******** schemas=RM dumpfile=exp_xe_rm.dmp logfile=exp_xe_rm.log directory=PUBLICO
Estimate in progress using BLOCKS method...
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 906.8 MB
Processing object type SCHEMA_EXPORT/USER
Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TYPE/TYPE_SPEC
Processing object type SCHEMA_EXPORT/SEQUENCE/SEQUENCE
Processing object type SCHEMA_EXPORT/TABLE/TABLE
ORA-39171: Job is experiencing a resumable wait.
ORA-01691: unable to extend lob segment SYSTEM.SYS_LOB0000098269C00045$$ by 128 in tablespace SYSTEM
ORA-39171: Job is experiencing a resumable wait.
ORA-01691: unable to extend lob segment SYSTEM.SYS_LOB0000098269C00045$$ by 128 in tablespace SYSTEM

Estou abortando o processo, mas infelizmente minha tablespace SYSTEM está em 97%, provavelmente cheio de lixos de import/exports anteriores.

Alguém sabe o que posso fazer?

Parece que não posso extender a tablespace SYSTEM, e eu não sei como retirar a lixarada dela.