I just bought me a house maybe a week ago and have been living there for almost a week.
I have oil heat in the building and I have all kinds of plastic vents in every room for the heat to come up.

My questions is can my cats or dog or maybe even a rat or snake lift them up and get into them??
One is really big like 3 feet long and 1 foot wide (and it's metal) but the rest are like 1 foot long and 1/2 foot wide (made from plastic).
I'm worried my cats can lift them up and get in. They are not bolted down and are light plastic?? I could screw them down but I need to take them up now and then and clean them out. They would probably have to lift them maybe 3-4inches before it comes out but I can see a cat doing that perhaps...Velcrow maybe?? I have new click flooring and didnt really want to ruin it just yet...
any suggestions???