Oh evil! Someone has an alchemy lab before I do?
*plots insidiously*
In all seriousness I can help you with any alchemy questions too if I'm around in game.
I like to use a 'brush' phys-rep to apply weapon coatings - but don't smear anything on someone else's weapon. I use a small basting brush. The book suggests its a possibility to smear petroleum jelly, but there's no reason to, affixing the tag is much better overall. (If you do use jelly for weapon coatings - the coating only lasts as long as the jelly itself does - which is very minimal. If you don't use the jelly it lasts 'indefinitely' which means it can last over several events if unused! So you not only save having to smear some icky stuff on a weapon, it also can potentially last longer too) If you don't have a brush with you - doing a 3 count "Applying coating 1, applying coating 2, applying coating 3" works just as well, but I personally believe the brush should be as much a required prop as a hammer & bandages for refit & first aid, so I try to use them
The only time you'd want to use petroleum jelly is for some kind of temporary contact thing where you are trying to trick them into it - and the only thing I can think of that players have for that is Paste of Stickyness (Plot team has 'contact poisons', but players can't make those). Anything else can be rped amicably and both players can agree on the resolution and no need to actually smear anything with nasty oil-based gunk (even paste of stickiness, if you want to glue someone who is unconscious to the table or something - you just tell the player you are using it - I considered doing that to one NPC a few events back who was sleeping and wasn't sure when he'd wake up)
One thing about the 'alchemy lab' physrep - Portability (the suitcase suggestion) works - but the main 'components' of the lab are somehow 'tied' to parson's breach (heavy equipment etc). If a session were to be held anywhere but parson's breach (or wherever you based the lab) you couldn't use it if you were in an event that takes place somewhere else. They are location dependant. Having a 'table' set aside in your cabin works well - there are no specific requirements for the phys-rep, it's more of an RP thing. The stuff I may have shown you in August or September are stuff ready for my workshop - the beeswax candles, the incense, the mortar & pestle, the large plastic 'jars' and the 'flavouring salts' (which is really just strawberry coolaid) and various dried herb leaves. I keep it all with me when I RP working, but I don't actually have the 'workshop' in game yet (Laront was going to sponsor one for me, but I'm now not sure if that's still part of the plan as things have kind of been up in the air with Math lately).