What 3rd party software is good to clean up your Mac?

Macs do not accumulate filth the way "those other computers" do. There is no need for general cleaning.

Instead, consider what your specific problem is, and Readers would love to help you examine and address it.

Seconding Grant's observations about "cleaning up", could you please tell us why you decided you need to clean up? Depending on what you want to do, eg. get rid of useless files, defragment the drive, or what ever, there may not be one single tool that does it all. And you may not need any cleaning up...

So perhaps you could tell us what you want to do, and why.

clone the system to a new hard drive

move the /Users/myaccount/ data and media folders to another hard drive

keep the boot drive to only OS + Apps and ~/Library and small

those things are junk, or worse.

use SuperDuper or Carbon Copy Cloner

don't clutter a disk drive and keep drives to 50%

A $100 SSD or 250GB WD 10K VR make a nice system drive or even 1TB WD Black

I have same 1,1 except only 4-core but with SSD, 10K VR, WD Black and another green 1.5TB for backup. And make sure you have RAM you need, say 4x2GB minimum or 8x2GB (and those woudl cost $70 or $140 on Amazon for the very best FBDIMMs for our Mac)

Defrag does help, but it probably will not bring back that "new mac, all is well" feeling. If you have the software - I use TechTool Pro - and the time, by all means do it.

I recently installed SSD's - officially that is a "solid state drive" - in a Macbook and a Mac Mini. (I am now convinced that ssd stands for "super sonic drive".) For small incemental gains, cleaning out the drive of excess filth - as Grant has described it, and defragmenting will certainly help. But for a really big perfomance boost you might consider replacing your drive with a SSD.

As for your question about whether 3-rd party cleaners are of value, the answer is, "Yes, definitely, but only to the vendors of that garbage."

How much is your system drive using now?

With an SSD aim for 50% free too.

$100 buys you a 128GB SSD which is usually fine for Mac and apps and tiny 2GB for that ~/Library

Summer but what model? yes that should be new current or latest model and WD Black or similar.

I get crazy with dumping all the cache that web browsers leave on the hard drive. Faster to just pull down and not search or not load all that junk into memory.

Make sure your modem and router are up to snuff and getting the best you can and test for speed and ping on Speedtest.net once in awhile.

I like SSD even though it is on the older SATA2 and can't tell difference other than quiet from the 10K WD VR it replaced (and use with CCC).

CCC and SuperDuper do SMART changes-only updates and generally take 10 minutes to update your backup and t he system only needs a backup before making changes.

Data needs much more frequest daily or more often.

And 10K WD VR may not have the lowest seek, but it is solid consistent and not subject to the whims and laws of SSD either. So good investments.

2-4TB drives make excellent fast data storage drives. And cost.

Would replacing main HD with SSD speed it up or would it be better for storage drives? I think I already know, but wanting confirmation.

Replacing the main HD is what makes sense - the speed, or lack thereof, of the storage drives does not really change the way the computer "feels" when you use it.

With the main HD, weeks after I did my replacements, I am still surprised at how fast Safari is, how quickly MS Word opens, etc. etc.