Disk Clean utilities , a few questions .

[Abraxas]

I know there's been quite a bit of discussion here on particular issues concerning Temp file cleaning , what I would like to know is some of the wildcard settings , and what they would actually do .
Basically my point here is that if you delete certain file types by inadvertently checking something you shouldn't it can cause trouble.
In CCleaner I note there's an option to delete the uninstallers for Windows updates. I ran it one day to see how much space could be saved and it was around 150 megabytes or more . I opted not to continue, mainly because it may be necessary to un-install an Update . (No I'm not going to mention the "Prefetch " option  , forget I said that  )

I'm looking at HDCleaner at the moment. It has these options, which seem to me a bit dangerous because of my lack of knowledge :
File Masks
_
_*
??~
_mp
~**
bak
chk
gid
old
syd
tmp
Out of that list all I would select is"temp" .
I'd be interested to hear from some people with a better understanding what the heck could happen if you selected the regular expressions like _ , _* , ??* , _mp , ~** .
I'd like to know  more about Temp file cleaning, I'm sure I've deleted important/useful things in the past .   
'0' byte files is another questionable option for deletion. So what's safe diskcleaning , and what's not   

 Just found some more in another diskcleaner and wondered what impact " cleaning " could do to Windows or other programs :
.bak , .gid , .old , File_id.diz , .tmp , .dmp , mscreate.dir , scandisk log , .chk .

Sorry to seem so ignorant , or lazy , but I'd sure like to know when and if some of these file types should be deleted, and what better place to ask than here 
Any light shed on this would be greatly appreciated ... Thanks.

[Lisandro]

Manual deletion (with a previous bakcup  ) is the *only* safe method...

Anyway, temporary files set could be:
*.~??, *.~~~, *.---, *.??~, *.#Res, *.$$$, *.$db, *.@@@, *._mp, *.aps, *.as$, *.asd, *.bak, *.bsc, *.cdr_, *.chk, *.da0, *.dar, *.db$, *.dir, *.dmp, *.ftg, *.fts, *.gid, *.ilk, *.mscreate, *.mtx, *.ncb, *.old, *.pch, *.rws, *.sbr, *.shs, *.syd, *.syd, *.temp, *.tmp, *.wa~, *.wbk, *.xar, *.xlk, chklist.*, mscreate.dir, File_id.diz, scandisk.log

I don't know more about:
_ and _*

Hope this helps.

[Abraxas]

Tech:

Manual deletion (with a previous bakcup   ) is the *only* safe method...

Thanks Tech , I guessed as much    Obviously using *.bak would delete the backup though ... 

[Lisandro]

Obviously using *.bak would delete the backup though ... 

Oh, I mean an external (USB or floppy) backup.
But, seriously, I don't think it's necessary.
The most dangerous extension among them (if any) is *.dir
You can remove it and you'll be safe. I won't worry that much 

[Abraxas]

Thanks Tech for clearing that up . When in doubt do nothing, then ask what may seem like silly questions 
-Cheers mate.

[RejZoR]

This extension cleaning is not accurate anymore.
All i'm using is my TEMP Cleaner. Most of junk leftovers are located in TEMP folders anyway...

[Lisandro]

This extension cleaning is not accurate anymore.

Do you have the 'accurate' one? I mean, the set of extensions?

[RejZoR]

Problem is that many programs and games started using these extensions.