For future reference acetone will have significant adverse effects on:
Polystyrene, polysulphone, PVC, polycarbonate, polyethylene, ABS, Nitrile, silicon, viton...
But is apparently compatable with polyproylene, PTFE, Acetal & nylon.

Interestingly isopropanol is not recomended with nylon but is OK with most other plastics.

I doubt acetone will do anything to the coatings, from what I've read the coatings are inorganic compounds such as magnesium fluoride which will be fine. However it attacks many plastics VERY strongly, so using it in situ is likely to affect the casing.

I've got a listing at work of which plastic are compatible with different solvents - I'll see if I can find it. I suspect the FA casing is polycarbonate which doesn't have good solvent resistance IIRC.

I suggest you take 'doingthebobs' advice first, then if you need to remove the blob consider dismantling the lens so it can be cleaned away from the casing. Of course from your description it may be that the blob isn't superglue so try some weaker solvents first!

Dave if you can keep it to charity shops & car boots LBA shouldn't cause you too much of a problem.
The trouble is it expands to e-bay, and then the expensive new lenses...

The rear focus distance for OM lenses is 46mm, (about 1/2mm more than the PK mount) so if the mount fits inside the PK body an adapter would be possible, I do't think it does - but I've never tried.

For macro work you can get adapters to allow the use of just about any lens on any SLR (with a bellows in between). Some bellows systems have adapters to directly couple the lens mount & camera mount, giving a lens/camera adapter with less extension but even with this sort of connection maximum focus distance will of course be relatively short in most cases.

Freelensing is also a possibility for incompatible camera/lens mounts but runs the risk of dust on your sensor and is often only possible for close up/macro work.

There are also adapters made for some camera lens combinations that include an optical element to extend the back focus distance, getting round the infinity focus issues - This will degrade the image quality somewhat. It might be possible to rig something similar yourself by modifying a teleconverter, using the OM mount from a set of cheap extension tubes for example.

Of course there are also T2 & adaptall lenses which are designed to work with adapters to mount on just about any SLR.

It might be possible to get the lens converted to a M42 or T2 mount allowing it to be used with appropriate camera adapters on either camera.

Unless your OM lens was really stunning I suspect any adaptation will cost far more than it will be worth. There are loads of affordable PK zooms covering this focal range many of which are optically quite good. (My sigma 70-210 proved somewhat of a dog though)

I've used a cheap Tasco scope, to photograph powerboats at over half a mile. Results were better than I would have got cropping a shorter lens but not by much. The images just looking through the scope being much better.
I suspect that the camera amplifies any errors in the scope - so as said above an excellent scope is required to get good results.
You'll also need a VERY sturdy tripod, & careful focusing - with no aperture control the focus varies considerably at distances most of my telephoto lenses would think were well into the infinity band.

I think I've seen various adapters that give HDMI ports for tablets on e-bay. So that MIGHT give you an option...

It was certainly fairly dark here - Wretched rain clouds!

I often use my flash on the end of a TTL cable, set up is easier than mounting the camera on a tripod & its a lot lighter to carry!
The flash is generally held out to on side at arms reach, and easily redirected if a more grazing or more direct light is beneficial.

With static subjects under high magnification a tripod comes into it's own - but only if you have a focusing slider. In the wilds I rarely find flowers/insects are static enough for a tripod to be any help.

200V is fairly typical for older flashes.
It is possible to get / make a little isolating circuit to go between the flash & the camera (effectivly a relay). It's been on my to do list for a couple of years but I find TTL too useful so I probably won't every bother.

Another possibility is to use an optical slave to trigger the old flash. I've seen slaves going for under £5 and the older ones were designed for higher trigger voltages. If I ever play around with multiple flashes (more than just the inbuilt flash & one remote) I'll probably be looking for where I left my slaves & flashes...

I never found one that had the features I wanted, (Aria mount in 2 directions + handstrap) so ended up making my own.
The Mk1 version (I've been using for ~2 years) isn't perfect as it gradually gets slightly loose, if I forget to tighten it every couple of months, allowing the camera to wobble on the tripod.
Construction was simple with the recessing of the screw the only bit that couldn't be done with basic handtools.
I keep promising myself I'll make an improved version that locks onto the rear edge of the camera - but in my free time I generally prefer to be taking photos...