Tenant illegally use

[Lena S.]

Hello,

What method do you use to prevent hacking coin operated washer/dryers?

We just found out one of our tenants (We have 4 unit property) use our coin operated dryer for free. They were able to hacked it. Now, we are going to place hologram stickers on washers and dryers and see how it works. Can we place a note on the wall  warning about eviction If tenants continue such activities? 
thank you for ideas.