UITableView memory issues - objective-c

Question

I'm adding UIView in some Cells of my UITableView. I use dequeueReusableCellWithIdentifier and it seems that when I scroll up and down and up and down, the views are never removed from memory and it keeps adding new views in front of the already loaded views. It increases the memory forever and that's not the way it should be.
How to remove these UIViews's from memory when not displayed ?
else if (indexPath.row == 0 && !isPremium) {
// Google AdMob
adCell = [tableView dequeueReusableCellWithIdentifier:adCellId];
if (adCell == nil) {
adCell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:adCellId];
}
AdMobView = [[GADBannerView alloc]initWithAdSize:kGADAdSizeSmartBannerPortrait];
AdMobView.adUnitID = #"ca-app-pub-XXXXXXXXXXXXXXX";
AdMobView.rootViewController = self;
AdMobView.autoresizingMask = UIViewAutoresizingFlexibleWidth;
// load the ads
GADRequest *request = [GADRequest request];
request.testDevices = [NSArray arrayWithObjects:GAD_SIMULATOR_ID, #"XXXXXXXXX", nil]; // COMMENT THIS LINE WHEN IN PROD
// add gps
if ([latitude length] > 2 && [longitude length] > 2) {
[request setLocationWithLatitude:[latitude floatValue] longitude:[longitude floatValue] accuracy:50]; // accuracy [m]
}
adCell.backgroundColor = [UIColor colorWithRed:247.0/255.0 green:149.0/255.0 blue: 24.0/255.0 alpha:1];
if (!AdMobView.superview) {
[AdMobView loadRequest:request];
}
AdMobView.tag = 3000;
[adCell.contentView addSubview:AdMobView];
[adCell setSelectionStyle:UITableViewCellSelectionStyleNone];
return adCell;
}

Answer 1

If the cells are being reused but the views are still piling up, that would be because in your cellForRowAtIndexPath: you are adding the views even to recycled cells that already have that view. Thus the views keep increasing in number, piling up on top of each other in each cell, as you scroll up and down.
Thus (now that you've added some code) you are saying:
[adCell.contentView addSubview:AdMobView];
...for every cell, unconditionally. But if a cell is reused, it already has an AdMobView! You need to check for this so you add this subview only conditionally (and so too for any other subviews you add).