When mine are just to the point of throw it away, I remove the bridge and cut the wick from both sides of the coil so all thats left is a coil with wick inside of it. Then run it under hot water upside down for a bit- blow it out repeat a few times. Look at it under a light and scrape any gunky buildup that didnt come off with whatever tool i have handy and repeat the water thing. Now i place it about 4 inches away from a hairdryer and let it sit to dry for 10-15 mins.
After this u can slap it on a battery- preferably a big battery and do a few dry burns, you cant hold the button for too long or u pop the atty and it reallly is trash. watch for it to glow orange, only takes a few seconds then stop give it just a bit to cool 20 seconds or so do another dry burn. You can get it orange and let off till its normal hit again till its orange let go til its normal repeat this just a bit now let it cool down completely. Sometimes i do the water rinse again if i feel up to it at this point other times i dont. Now you drop about 5-7 drops onto the wick let it soak a few seconds tap the battery a couple times put 2 more drops on and start
vaping.
At first it may seem like its not working well but it just needs to break in a bit or if it tastes funky it will go away with some use. Ive gotten the very best hits ever off of atties that would normally have been thrown away but after this process work like a dream. They eat up liquid fast since its a small wick thats left but oh well. sorry for this being longwinded and not very nice looking lol but im in a hurry.
P.S. Only do this with atties that are poor performers that you dont really care about because its easy to completely break them doing this. Although ive done this to 6 atties and broke 1 during the process, the other 5 worked for anywheres from 1 weeks to 1 month after giving monster rips the whole time.