how to remove "this site may harrm your comouter"?

site was hacked. been trying to clean it up since this morning. after a lot of googling, i think I managed to get rid of all the shit.
now I want google to remove site from the blacklist

is it enough if i just ping the website? next time the bot visits, it wont see the malicious code any more and remove the message?
or do I have to add the site to webmaster tools? I really really want to avoid webmaster tools if possible.

An expert SEO'er such as yourself should be aware that this has been discussed many times on BHW, but anyway, these should help:
https://www.stopbadware.org/request-review
https://support.google.com/webmasters/answer/163634?hl=en
https://support.google.com/webmasters/answer/168328?hl=en

Can I ask why do you wan't to avoid Webmasters tools?

I think there was no way to remove it but to have the site reviewed by thru webmaster tools.

I believe you are talking about the black/grey screen with some warning that people see when they try to visit any page in your website. I had such a problem about 5 months ago and i just didnt know why, I visited support.google forums but i couldn't find a good solution to this.

What I did:
I used wordfecnce plugin to scan the site and I found that it was an issue with images, that is what was pointed out. I didnt want to use other images so what i did is renamed them all. Next, I resubmitted my site to webmaster tools and then I sent a ticket, if i remember well. There is something like that over at webmaster tools. I waited for about 4 days and the problem was resolved.

Hope that helps,

I think webmaster tools would offer you the best platform to remove this.