finding and replacing registration colour

I know this has been discussed before but I can't seem to find the topic.

The question is: is there a way of finding all instances of the registration colour and replacing it with black? I have some documents to output in which registration is used quite a lot, for some obscure reason.

I can find the text filled or stroked with registration and replace the colour in the find/change dialogue box but it's frame and frame fills that take the time.