I agree with Axel's post. I have , thoroughly tested, third party products on my computers, which have passed the test of time. The most prominent, used all over the IT world, is Ccleaner. Worth pointing out here, also, that Ccleaner has an extensive list of options regarding what exactly you wish to "clean". And yes, it does have a registry cleaner option. I have tried it and found it does no harm. But I agree with the comments in this thread - it serves no useful purpose to "clean" the registry. the items removed by cleaningare, in essence, so small that it does not noticeably slow down computer performance. Furthermore, since Window's 10 and its compulsory updates, from time to time, a whole new registry comes along buried in the cumulative ones. - Makes cleaning a superfluous waste of time.
FWIW. Both Ccleaner and the disk clean trick, outlined above, both leave a ton of temp files behind.