#1
These Is a guitar I bought for like 150 bucks, pretty old. I changed new strings, cleaned it up a bit..

But there is two problems, I don't like the tone compaired to other guitars.
Its dull and it lacks of brightness, and when I twist the tone knob, even gently it makes a noise.

Based on my search I should try different caps, the guitar setup is just fine..
#2
.....or replace the scratchy pot. When soldering the pot could've gotten too hot and been damaged. I'm not an expert but I'm pretty sure I read that somewhere before.
#3
The dull tone may be the wood. Old doesn't always mean better tone. I say overhaul all the electronics. New pots, caps, fresh wire, jack. Should be less than 25 bucks for it all and an afternoon of soldering. You'd be surprised what it will do.
Harmony: Stratocaster
Alvarez: F-200
Schecter: Omen 6
Fender: BXR-60
Dean: Metalman Z Bass (Betty)
Egnator: Tweaker 15
Pearl: Maximum
ESP/LTD: EXP-300
Custom: Harley Quinn Bass
Custom: TK-421 Explorer
A steadily growing supply of pedals
#4
If the pot is scratchy you just need to replace the pot itself. New cap won't do anything for that.

As far as the tone, you could try higher value volume and tone pots (as long as you're replacing them anyway) and adjusting the pickup height, but there's always the distinct possibility that it's just a crappy sounding guitar.