Artificial coral will need regular cleaning, approximately every 2 weeks. You will also periodically need to completely remove the coral in order to do a deep clean.
One tip is to buy a second set of coral and much like filter socks, you can rotate them. So, while one set is waiting to be cleaned, you can have another ready to go into your tank. This way, you won’t get bored of looking at the same display and can also change the position of the corals when putting them back in your tank.
The process of cleaning coralline algae is exactly the same for cleaning fake coral.
The coral can be soaked for a few hours in a solution of 50/50 water and distilled white vinegar.