Delete all messages in discord channel, the lazy way using mee6.xyz (add bot + enable moderation + enable !clear). When all messages are gone you can either refresh or run `stop_purge = true` in dev tools.

purge_channel.js

var stop_purge = false;
(function(){
  // Go to the channel you want to purge completely (in browser, discordapp.com)
	// Open your chrome dev tools (ctrl+shift+i), go to the Network tab.
  // Send a message and it should show activity in the network pane. Click on the request you made, the name should be "messages"
  // Click on the request, copy the "Request URL" and paste it in between these quotes:
  var requestURL = ''

  // scroll down to "Request Headers" and grab the key behind "authorization:" and paste it inside these quotes:
	var authToken = ''
	
	// paste code (with your codes above) in the console tab, run code (press enter)
	
	// https://github.com/yanatan16/nanoajax
	!function(t,e){function n(t){return t&&e.XDomainRequest&&!/MSIE 1/.test(navigator.userAgent)?new XDomainRequest:e.XMLHttpRequest?new XMLHttpRequest:void 0}function o(t,e,n){t[e]=t[e]||n}var r=["responseType","withCredentials","timeout","onprogress"];t.ajax=function(t,a){function s(t,e){return function(){c||(a(void 0===f.status?t:f.status,0===f.status?"Error":f.response||f.responseText||e,f),c=!0)}}var u=t.headers||{},i=t.body,d=t.method||(i?"POST":"GET"),c=!1,f=n(t.cors);f.open(d,t.url,!0);var l=f.onload=s(200);f.onreadystatechange=function(){4===f.readyState&&l()},f.onerror=s(null,"Error"),f.ontimeout=s(null,"Timeout"),f.onabort=s(null,"Abort"),i&&(o(u,"X-Requested-With","XMLHttpRequest"),e.FormData&&i instanceof e.FormData||o(u,"Content-Type","application/x-www-form-urlencoded"));for(var p,m=0,v=r.length;v>m;m++)p=r[m],void 0!==t[p]&&(f[p]=t[p]);for(var p in u)f.setRequestHeader(p,u[p]);return f.send(i),f},e.nanoajax=t}({},function(){return this}());
	var deleteLoop = function(){
		if (stop_purge) { return }
		nanoajax.ajax({
			url: requestURL,
			method: 'POST',
			headers: {
				authorization: authToken
			},
      body: "content=!clear 100&nonce=213196997010653184&tts=false"
		}, function(){
			setTimeout(deleteLoop, 3000)
		})
	}
	deleteLoop()
}())