hey,
i use nitromors paint stripper. It tells you how to do it on the back of the tin but...
here it is..
apply a thick layer with a paint brush using a dabbing motion . ( more the better in my case )
wait for 5 minutes.
apply another layer targeting blistered paint !
Leave for 20 minutes.
DO NOT let it try out , apply more in case,
clean off with water of something ..
hope this helped ..
matt