Yes- every section of the black frame is hollow! like hollow box section. The top corners have blanker covers over them but the feet do not. There are 4 long sections and 8 shorter ones. All are hollow and all have deep grooves for the perspex to sit in. The corner connectors also harboured bugs and were tricky to clean and dry with all the nooks and crannies.
( you might remember that the last time I gutted out the tank for these bugs I noticed one on the bottom of one of the legs almost as soon as I sat down when I was all finished and Mr Maggie was back in there... which made me wonder if there were some inside the frame. I had hoped it was just a lone survivor but was keeping an eagle eye out and sure enough they came back with a bang)
It was VERY difficult to clean the framework out- especially the 4 longer sections as they don't fit in the sink! If you have a bath then you could probably more effectively soak/clean using that. (we do not!) they are also not very wide openings so cant even use a bottle brush or anything like that (length would be an issue too)
I didn't hoover anything this time (other than the room). I took the tank outside and dismantled it there then cleaned all the parts in sections.
The short sections of the frame I cleaned in the sink. I couldn't submerge them but cleaned down the exterior and used a cup to pour the cleaning solution through them. I confess I did use bleach because these are parts of the tank which will not be in contact with Mr Maggie. They were thoroughly rinsed with clean hot water afterwards and THEN I sprayed them with vinegar solution which I let sit before cleaning off and leaving to dry. I was able to spray vinegar solution in through these but just how effective this was I will never know.
The longer sections I had to just blast with the outside tap/hose to flush them out before then spraying vinegar into them from each end. I just have to hope its been enough.
I will say that they are very difficult to dry as well! I let them drip dry and gave them a bit of a shake then had to resort to using my hair dryer on them.
His bag of food (which is nearly finished) was in a sealed tub and I cant see any evidence of infestation in there. I had to use this to replace his hoard so there are a few spoons back in the tank as well as in his bowl. I have a new bag of food in the freezer which should be ready by now. (I forgot to make a note of when I froze it so am leaving it a few more days) feel quite paranoid now about them coming back again. I have just put his science selective pellets in the freezer too just to be on the safe side as there was one bug on the lid of that container (sits under the table where the tanks was)
I have new sprays in the freezer but they wont be safe to use until next weekend. I've just ordered a few new bits too but will need to wait for them to arrive and be frozen so will be a while before I can use them. I think I will chuck all the sprays but would like to save the bigger things like his tunnel and coconut hide, as well as his pressed floral disc and lotus pod etc. I think for those I will freeze for a week, thaw for 24 hours then freeze again a week to try and ensure that any bugs and eggs are dead. may all be futile!
I'll keep my fingers and toes crossed for us both Maz!
sending a virtual hug and lots of strength 
So are the legs hollow? That is worth knowing about for future reference. If that's the case, it's almost as difficult to disinfect as a Savic Plaza cage - although the difficult bit on the plaza is disinfecting all the bars 
ensuring full coverage. I tended to spray them but then rub over with a very soapy sponge inside and out so the soap went round every bit of all the bars and then rinse it off. At least the perspex is easier to disinfect on a Bucatstate.
I better oder another pack