Everyone doesn't like being spied in war. Of course, if you say anything about you are a spy and leave the clan after you destroyed their bases they would definitely regret opening the clan for enemy spies to join.
Now, almost every professional war clan closes their clan when they are engaged in war. War spies aren't allowed to join the clan normally.
But, we can expose this trick of anti-war spies by using the not-so-good relationships with the clan leader and the elder.
When a clan is closed, elders have permission to invite people. Usually, elder is given for people who are not familiar with the leader in real life or have not so much contribution to the clan. We can use these elders to invite our spies to the enemy clan.
But how are we convincing these elders to invite our spies to the clan? First, we have to understand the elder's background and his connection with the leaders or co-leaders. The co-leaders and leader usually close the clan because they understand this could prevent spies from entering clan. If we friend request one of the noobish elders which do not have the same name as one of the co-leaders( For instance we are warring against a BD clan lately and we want to spy enemy clan. I saw many Tuhin names in the clan and one of them is a coleader So, Do not friend Tuhin even if he is an elder, because he might be actually close to the leader that he has brought many accounts for the clan.
Wait for the elder to accept your request. Then, get some research of the language the elder is using( If that player is Indian or BD, you can use English). After that, make a new clan based on the "invite me plzz" word. (If you spy on other languages clan, use that language with translation service). Then, the elder would probably invite you to the clan. If you do this to a co-leader, he would not invite you because he understands the clan is deliberately closed due to the prevention of war spies. But, elders do not have much contact and thus do not understand the use of closing clan and not inviting random people to the clan.
You have to be patient. Wait until he invites you. If he seems offline or doesn't invite you, friend another person who is only an elder in the clan. Eventually, some noobs will invite you because he doesn't understand more about war spies as the co-leaders do. Good Luck Joining The enemy Clan! Remember to immediately snapshot all the bases and send them to your members. Also, do not chat unless you are greeting others in their language, also remember not to leave until war day starts as they might change their bases and cc troops once they realise you might be a spy.
When war day starts, feel free to leave a taunting message for your opponents and challenge them to beat your bases in war. This makes a bad feeling of the enemy clan and they think that no war spies can join but one just entered silently and stole all their bases, cc troops and just 100% destroyed them. This severely lowers enemy's attack success rate as they have been vandalized all their info of war and they just get destroyed. This way, you are getting a higher chance of winning the war rather than drawing it.
If you are reading this article, you might realize others are also doing this strategy to your clan: friend elders and ask them to invite to your them as their alertness of spies entering is way low then the co-leaders. So, what's the best way to get rid of this?
1. Do not promote anyone to elder unless they are really trustable.
2. Tell all people not to invite people who have friended them recently.
3. Only give co-leader to people who you know in real life, and you can depend on them to kick out war spies that are suspicious.
P.S. I hope you're not using this strategy against us if you really matched against us in war, because we totally depend on this little trick to spy on invite only/closed clans. We already have a 14 war streak so please don't do this against us or block our clan from spies. We don't want to lose our streak.
Good Luck In Wars!