What do you mean remove a spell that was found? Where was it found and why do you want to remove it?
If it is published here on the site, reporting it may be helpful if its contents are truly inappropriate. If you simply do not like the spell, that may not be enough to have it removed.
if you found a spell post on here you feel is inappropriate [swearing or promoting self harm. i've found some encouraging suicide in the past] then you need to scroll to the bottom, click the 'report spam' button, then copy the url and send a private message to Petrarca about it. it will be down within the hour [or sooner if he's online] however, if this is just 'how to become a vampire' or any other non working fluffy bunny-esque spell that just annoys you because it's not real magick, unfortunately, it stays. those spells [while fake. i cannot stress enough how much they do not work] bring traffic to the site and ad revenue which keeps this site free for those who really wish to learn [and might even introduce those who don't know about magick to the path and bring great things to their life. you never know]
if you mean spell reversal as in 'cast this spell and i regret it, help me undo what i've done' i would first like to say 'tisk-tisk, this is why you think before you cast' [or to quote Practical Magic 'you can't practice witchcraft while you look down your nose at it'] but we all make mistake, realize we did wrong, and wish to correct things [or sometimes we get an enchanted object we need to defuse] depending on the spell there's several things you can try. if you cast something along the lines of a candle spell, chant, or something where you didn't make anything [honey jar for example] you could try a very easy 'i'm sorry' chant. basically light a white candle and say a little chant along the lines of 'what was done, now undo, cleanse the energy i once cast, forgive the mistake of my past' [and visualize the energy returning to you, or being purified] then snuff out the candle. [you might also consider burning some sage or having a sea salt bath to remove any energy] if it was something like a honey jar, poppet, crystal, candle, or whatever you either made or infused with energy, take the item and place it in sea salt water and say a reversal chant. [for a honey jar, cleanse it, then dump the contents in running water and walk away without looking back. this should take it far away from you] with more potent things like someone gave you a cursed ring, or you seem unable to undo the enchantment on something, you can place it in a mirror box and bury it off property, or place it in a box, fill it with salt, and bury it. the mirrors will contain the energy while the earth will cleanse/ground it [salt works similarly, but some avoid it in case it tarnishes a metal object and it seeps into the ground]