There's multiple ways of doing things in batch, so if escaping with a double percent %% isn't working for you, then you could try something like this:
set olddir=%CD%
cd /d "path of folder"
del "file name/ or *.txt etc..."
cd /d "%olddir%"
How this works:
set olddir=%CD% sets the variable "olddir" or any other variable name you like to the directory
your batch file was launched from.
cd /d "path of folder" changes the current directory the batch will be looking at. keep the
quotations and change path of folder to which ever path you aiming for.
del "file name/ or *.txt etc..." will delete the file in the current directory your batch is looking at, just don't add a directory path before the file name and just have the full file name or, to delete multiple files with the same extension with *.txt or whatever extension you need.
cd /d "%olddir%" takes the variable saved with your old path and goes back to the directory you started the batch with, its not important if you don't want the batch going back to its previous directory path, and like stated before the variable name can be changed to whatever you wish by changing the set olddir=%CD% line.