BBPress: mass delete of topics and remove old shortcodes

Hi, I have imported a forum from vbulletin to bbpress. Now I have to clean it and some functions are not available, so need to to them through phpmyadmin, I suppose. There are 2 goals: 1) mass delete of topics. I need to delete all topics under subforum x, y, z, etc. Since it's better to delete topics via wordpress admin to be sure not crash the database, the "mass" query should consider every operation made a delete via admin panel, and replicate it (I think for example updating number of topics, etc.) 2) remove shortcodes. In new forum many of them not works anymore, so need to clean. For example: [googlemaps]address[/googlemaps] --> address [ATTACH=CONFIG]10342[/ATTACH] --> remove everything [SIZE=4]text[/SIZE] .---> text <a href="http://url-ow-webiste">text</a> --> url-of-webiste I think there are about 5/15 types of replaces to do. Feel free to ask further details, thanks