Host cache on ESXi 5.1 free is full

Hi

I have the SSD disk where host cache is full of 42  1 gb's files

ssh df -h

Filesystem   Size   Used Available Use% Mounted on
VMFS-5       1.8T   1.4T    416.8G  78% /vmfs/volumes/vm2000gb
VMFS-5      51.0G  50.9G     53.0M 100% /vmfs/volumes/datastore1
VMFS-5     931.2G  34.6G    896.6G   4% /vmfs/volumes/vm1000gb
vfat         4.0G  10.9M      4.0G   0% /vmfs/volumes/50d9e74a-72d6c8a3-ca1a-f46                                                         d041ca822
vfat       249.7M 130.2M    119.6M  52% /vmfs/volumes/2e644870-ea8e3e34-efd8-a84                                                         e9a4164b0
vfat       249.7M   8.0K    249.7M   0% /vmfs/volumes/46cee273-423121fe-22a0-3ad                                                         cb157c839
vfat       285.8M 201.9M     83.9M  71% /vmfs/volumes/50d9e733-8513e425-fdb4-f46                                                         d041ca822

the host cache is on datastore1

how can I delete the files, after I will set hostcache to 25GB

Claus