One of my cars has multiple rust water stains from parking in a shitty garage (most expensive one in the area but I hate it now oh well)
They are about 3-4 months old atleast. I hope its not too late to get them out.

I googled and stumbled upon a similar issue. The fix was...
"We ended up using rubbing compound followed by polishing compound and the rust came out"

My question is...
1. Do I need any tools to use the rubbing or polishing compounds?
2. Can I hand apply wax after these jobs or should I get it professionaly detailed?
3. Any damage from rust water stains? (I am not able to scrape it off with a finger nail - not even a little bit - so worried if it will have eaten the paint or something?)

Thanks

 

clay bar

 

Prior to a clay bar and lube, try this product on the staining. It should loosen or remove most of the rust, then rinse and try the clay bar and lube

https://detailersdomain.com/Aquartz-Iron-Cut_p_327.html

 

I need to look this up, sorry. But, what is the difference between clay bar/polishing compound/rubbing compound?

More importantly, any idea if it the stain might have damaged the paint underneath?
And dont I need to wax it after clay bar (since that strips wax also). Can I wax it myself or need a pro (never waxed before)

 

I second ^^ iron cut or iron x will do the job, then clay bar, then wax/sealant.
you can wax it yourself. polishers will make the job go quicker, but you can just do it by hand...think karate kid.