In my app while testing I'm doing like that and it seems to work fine without any side-effects:
<code>
drop table act_ge_bytearray ,act_ge_property ,act_hi_actinst ,act_hi_attachment ,act_hi_comment ,act_hi_detail ,act_hi_procinst ,act_hi_taskinst ,act_hi_varinst ,act_id_group ,act_id_info ,act_id_membership ,act_id_user ,act_re_deployment ,act_re_model ,act_re_procdef ,act_ru_event_subscr,act_ru_execution ,act_ru_identitylink,act_ru_job ,act_ru_task ,act_ru_variable;
</code>
