It is allowed to use or rent or hire for religious activities including Namaz, Majaalis, lectures etc, a place which was or is used in un-Islamic way on other times. It is like the road where we walk on, which is used by good people and bad people. Every one is responsible of his acts.
No doubt, we need to be sure about Taharat in the place of prostration (Sojood) of Namaz.
Musical instruments and alcohol related items should be removed during the religious gathering to keep the respect of the religious activity.